Rename CommandTree to OldCommandTree

.gitignore

@@ -1,3 +1,4 @@
+Cargo.lock
 target
 .schala_repl
 .schala_history

Cargo.toml

@@ -2,14 +2,11 @@
 name = "schala"
 version = "0.1.0"
 authors = ["greg <greg.shuflin@protonmail.com>"]
-edition = "2018"
-resolver = "2"
 
 [dependencies]
-getopts = "0.2.21"
 
 schala-repl = { path = "schala-repl" }
-schala-lang = { path = "schala-lang" }
+schala-lang = { path = "schala-lang/language" }
 # maaru-lang = { path = "maaru" }
 # rukka-lang = { path = "rukka" }
 # robo-lang = { path = "robo" }

README.md

@@ -1,44 +1,22 @@
 # Schala - a programming language meta-interpreter
 
 Schala is a Rust framework written to make it easy to create and experiment
-with multiple toy programming languages. It provides a cross-language REPL and
+with multipl toy programming languages. It provides a cross-language REPL and
 provisions for tokenizing text, parsing tokens, evaluating an abstract syntax
-tree, and other tasks that are common to all programming languages, as well as
-sharing state between multiple programming languages.
+tree, and other tasks that are common to all programming languages, as well as sharing state
+between multiple programming languages.
 
-Schala is implemented as a Rust library `schala-repl`, which provides a `Repl`
-data structure that takes in a value implementing the
-`ProgrammingLanguageInterface` trait. Individual programming language
-implementations are Rust types that implement `ProgrammingLanguageInterface`
-and store whatever persistent state is relevant to that language. 
+Schala is implemented as a Rust library `schala-repl`, which provides a
+function `start_repl`, meant to be used as entry point into a common REPL or
+non-interactive environment. Clients are expected to invoke `start_repl` with a
+vector of programming languages. Individual programming language
+implementations are Rust types that implement the
+`ProgrammingLanguageInterface` trait and store whatever persistent state is
+relevant to that language. 
 
-
-## Running
-
-Run schala with the normal `cargo run`. This will drop you into a REPL
-environment.  Type `:help` for more information, or type in text in any
-supported programming language (currently only `schala-lang`) to evaluate it in
-the REPL.
-
-### Examples
-
-Try running the following `schala-lang` code example in the REPL:
-
-```
->> 1 + 1
-(Total time)=> 736.368µs
-=> 2
->> fn foo(x) { x + 10 }
-(Total time)=> 772.496µs
-=> 
->> foo(0)
-(Total time)=> 593.591µs
-=> 10
->> 5 + foo(1)
-(Total time)=> 1.119916ms
-=> 16
->> 
-```
+Run schala with: `cargo run`. This will drop you into a REPL environment.  Type
+`:help` for more information, or type in text in any supported programming
+language (currently only schala-lang) to evaluate it in the REPL.
 
 ## History
 
@@ -81,30 +59,33 @@ much like Haskell
 Here's a partial list of resources I've made use of in the process
 of learning how to write a programming language.
 
-### General
-
-* http://thume.ca/2019/04/18/writing-a-compiler-in-rust/
-
 ### Type-checking
-* https://skillsmatter.com/skillscasts/10868-inside-the-rust-compiler
-* https://www.youtube.com/watch?v=il3gD7XMdmA
-* http://dev.stephendiehl.com/fun/006_hindley_milner.html
-* https://rust-lang-nursery.github.io/rustc-guide/type-inference.html
-* https://eli.thegreenplace.net/2018/unification/
-* https://eli.thegreenplace.net/2018/type-inference/
-* http://smallcultfollowing.com/babysteps/blog/2017/03/25/unification-in-chalk-part-1/
-* http://reasonableapproximation.net/2019/05/05/hindley-milner.html
+https://skillsmatter.com/skillscasts/10868-inside-the-rust-compiler
+https://www.youtube.com/watch?v=il3gD7XMdmA
+http://dev.stephendiehl.com/fun/006_hindley_milner.html
+https://rust-lang-nursery.github.io/rustc-guide/type-inference.html
+
+https://eli.thegreenplace.net/2018/unification/
+https://eli.thegreenplace.net/2018/type-inference/
+http://smallcultfollowing.com/babysteps/blog/2017/03/25/unification-in-chalk-part-1/
+http://reasonableapproximation.net/2019/05/05/hindley-milner.html
 https://rickyhan.com/jekyll/update/2018/05/26/hindley-milner-tutorial-rust.html
 
 ### Evaluation
+*Understanding Computation*, Tom Stuart, O'Reilly 2013
 
-* _Understanding Computation_, Tom Stuart, O'Reilly 2013
-* _Basics of Compiler Design_, Torben Mogensen
+*Basics of Compiler Design*, Torben Mogensen
 
 ### Parsing
-* http://journal.stuffwithstuff.com/2011/03/19/pratt-parsers-expression-parsing-made-easy/
-* https://soc.github.io/languages/unified-condition-syntax
-* [Crafting Interpreters](http://www.craftinginterpreters.com/)
+http://journal.stuffwithstuff.com/2011/03/19/pratt-parsers-expression-parsing-made-easy/
+https://soc.github.io/languages/unified-condition-syntax
+
+[Crafting Interpreters](http://www.craftinginterpreters.com/)
 
 ### LLVM
-* http://blog.ulysse.io/2016/07/03/llvm-getting-started.html
+http://blog.ulysse.io/2016/07/03/llvm-getting-started.html
+
+###Rust resources
+https://thefullsnack.com/en/rust-for-the-web.html
+
+https://rocket.rs/guide/getting-started/

TODO.md

@@ -1,92 +1,37 @@
-# Immediate TODOs / General Code Cleanup
-
-## Parsing
-
-* cf. https://siraben.dev/2022/03/22/tree-sitter-linter.html write a tree-sitter parser for Schala
-
-* Create a macro system, perhaps c.f. Crystal's?
-    * Macro system should be able to implement:
-        * printf-style variadic arguments
-        * something like the Rust/Haskell `Derive` construct
-        * doing useful things with all variants of an enum 
-            * (e.g. what https://matklad.github.io//2022/03/26/self-modifying-code.html tries to solve)
-
-
-## Testing
-
-* Make an automatic (macro-based?) system for numbering compiler errors, this should be every type of error
-
-## Symbols
-
-* Add some good printf-debugging impls for SymbolTable-related items
-
-* the symbol table should probably *only* be for global definitions (maybe rename it to reflect this?)
-* dealing with variable lookup w/in functions/closures should probably happen in AST -> ReducedAST
-    * b/c that's where we go from a string name to a canonical ID (for e.g. 2nd param in 3rd enclosing scope)
-
-* In fact to prove this works, the symbol table shoudl _parallelize_ the process of checking subscopes for local items
-
-* Old notes on a plan of attack:
-
-1. modify visitor so it can handle scopes
-  -this is needed both to handle import scope correctly
-  -and also to support making FQSNs aware of function parameters
-
-2. Once FQSNs are aware of function parameters, most of the Rc<String> things in eval.rs can go away
+# TODO items
 
 ## Typechecking
 
-* make a type to represent types rather than relying on string comparisons
-* look at https://rickyhan.com/jekyll/update/2018/05/26/hindley-milner-tutorial-rust.html
+- look at https://rickyhan.com/jekyll/update/2018/05/26/hindley-milner-tutorial-rust.html
 
-## General code cleanup
-* standardize on an error type that isn't String
-* implement a visitor pattern for the use of scope_resolver
-  * maybe implement this twice: 1) the value-returning, no-default one in the haoyi blogpost,
-  * look at
-    * https://gitlab.haskell.org/ghc/ghc/wikis/pattern-synonyms
-    * the non-value-returning, default one like in rustc (cf. https://github.com/rust-unofficial/patterns/blob/master/patterns/visitor.md)
+- cf. the notation mentioned in the cardelli paper, the debug information for the `typechecking` pass should 
+print the generated type variable for every subexpression in an expression
 
+- change 'trait' to 'interface'
 
-# Longer-term Ideas
+- think about idris-related ideas of multiple implementations of a type for an interface (+ vs * impl for monoids, for preorder/inorder/postorder for Foldable)
 
-## Language Syntax
+-should have an Idris-like `cast To From` function
 
-* the `type` declaration should have some kind of GADT-like syntax
-* syntactic sugar for typestates? (cf. https://rustype.github.io/notes/notes/rust-typestate-series/rust-typestate-part-1.html )
-* use `let` sigil to indicate a variable in a pattern explicitly:
+## Schala-lang syntax
 
-```
-  q is MyStruct(let a, Chrono::Trigga) then {
-    // a is in scope here
+-idea: the `type` declaration should have some kind of GADT-like syntax
 
-  }
-```
+-idea: I should make the BNF grammar part of the documentation...
 
-* if you have a pattern-match where one variant has a variable and the other
-  lacks it instead of treating this as a type error, promote the bound variable
-  to an option type
+- Idea: if you have a pattern-match where one variant has a variable and the other lacks it
+instead of treating this as a type error, promote the bound variable to an option type
 
-* what if there was something like React jsx syntas built in? i.e. a way to
-  automatically transform some kind of markup into a function call, cf. `<h1
-  prop="arg">` ->  h1(prop=arg)
+- Include extensible scala-style html"string ${var}" string interpolations
 
-* implement and test open/use statements
-
-* Include extensible scala-style `html"string ${var}"` string interpolations
-
-* A neat idea for pattern matching optimization would be if you could match on
-  one of several things in a list
+- A neat idea for pattern matching optimization would be if you could match on one of several things in a list
 ex:
-```
-if x {
+```if x {
  is (comp, LHSPat, RHSPat) if comp in ["==, "<"] -> ...
-}
-```
+}```
 
-* Schala should have both currying *and* default arguments!
-```
-fn a(b: Int, c:Int, d:Int = 1) -> Int
+- Schala should have both currying *and* default arguments!
+```fn a(b: Int, c:Int, d:Int = 1) -> Int
     a(1,2) : Int
     a(1,2,d=2): Int
     a(_,1,3) : Int -> Int
@@ -94,84 +39,35 @@ fn a(b: Int, c:Int, d:Int = 1) -> Int
     a(_,_,_) : Int -> Int -> Int -> Int
 ```
 
-* scoped types - be able to define a quick enum type scoped to a function or other type for
+- scoped types - be able to define a quick enum type scoped to a function or other type for
   something, that only is meant to be used as a quick bespoke interface between
   two other things
 
-
 ex.
-```
-type enum {
+```type enum {
   type enum MySubVariant {
     SubVariant1, SubVariant2, etc.
     }
  Variant1(MySubVariant),
  Variant2(...),
- }
-```
-
-* inclusive/exclusive range syntax like .. vs ..=
-
-* Nameable patterns/ pattern synonyms cf. https://gitlab.haskell.org/ghc/ghc/-/wikis/pattern-synonyms
-
-
-## Typechecking
-
-* cf. the notation mentioned in the cardelli paper, the debug information for the `typechecking` pass should
-    * print the generated type variable for every subexpression in an expression
-* think about idris-related ideas of multiple implementations of a type for an interface (+ vs * impl for monoids, for preorder/inorder/postorder for Foldable)
-* should have an Idris-like `cast To From` function
-
-* something like the swift `Never` type ( https://nshipster.com/never/ ) in the stdlib
+ }```
 
+- inclusive/exclusive range syntax like .. vs ..=
 
 ## Compilation
-* look into Inkwell for rust LLVM bindings
-* https://cranelift.readthedocs.io/en/latest/?badge=latest<Paste>
+-look into Inkwell for rust LLVM bindings
 
-* look at https://gluon-lang.org/doc/nightly/book/embedding-api.html
+-https://cranelift.readthedocs.io/en/latest/?badge=latest<Paste>
 
 
-# Syntax Playground
+## Other links of note
 
-## Trying if-syntax again
-
-```
-//simple if expr
-if x == 10 then "a" else "z"
-
-//complex if expr
-if x == 10 then {
-  let a = 1
-  let b = 2
-  a + b
-} else {
-  55
-}
-
-// different comparison ops
-if x {
- == 1 then "a"
-  .isPrime() then "b"
-  else "c"
-}
-
-/* for now disallow `if x == { 1 then ... }`, b/c hard to parse
-
-//simple pattern-matching
-if x is Person("Ivan", age) then age else 0
-
-//match-block equivalent
-if x {
- is Person("Ivan", _) then "Ivan"
- is Person(_, age) if age > 13 then "barmitzvah'd"
- else "foo"
- }
-```
+- https://nshipster.com/never/
+-consult http://gluon-lang.org/book/embedding-api.html
 
 
-## (OLD) Playing around with conditional syntax ideas
 
+## Playing around with conditional syntax ideas
 
 - if/match playground
 
@@ -211,3 +107,17 @@ if the only two guard patterns are true and false, then the abbreviated syntax:
 `'if' discriminator 'then' block_or_expr 'else' block_or_expr`
 can replace `'if' discriminator '{' 'true' 'then' block_or_expr; 'false' 'then' block_or_expr '}'`
 
+
+
+
+
+
+
+
+
+
+
+
+
+
+

rust-toolchain.toml

@@ -1,2 +0,0 @@
-[toolchain]
-channel = "nightly"

rustfmt.toml

@@ -1,8 +0,0 @@
-
-max_width = 110
-use_small_heuristics = "max"
-imports_indent = "block"
-imports_granularity = "crate"
-group_imports = "stdexternalcrate"
-match_arm_blocks = false
-where_single_line = true

schala-lang/Cargo.toml

@@ -1,27 +0,0 @@
-[package]
-name = "schala-lang"
-version = "0.1.0"
-authors = ["greg <greg.shuflin@protonmail.com>"]
-edition = "2021"
-
-[dependencies]
-itertools = "0.10"
-take_mut = "0.2.2"
-failure = "0.1.5"
-ena = "0.11.0"
-stopwatch = "0.0.7"
-derivative = "2.2.0"
-colored = "1.8"
-radix_trie = "0.1.5"
-assert_matches = "1.5"
-#peg = "0.7.0"
-peg = "0.8.1"
-nom = "7.1.0"
-nom_locate = "4.0.0"
-
-
-schala-repl = { path = "../schala-repl" }
-
-[dev-dependencies]
-test-case = "1.2.0"
-pretty_assertions = "1.0.0"

schala-lang/codegen/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "schala-lang-codegen"
+version = "0.1.0"
+authors = ["greg <greg.shuflin@protonmail.com>"]
+edition = "2018"
+
+[lib]
+proc-macro = true
+
+[dependencies]
+syn = { version = "0.15.12", features = ["full", "extra-traits", "fold"] }
+quote = "0.6.8"

schala-lang/codegen/src/lib.rs

@@ -0,0 +1,50 @@
+#![feature(box_patterns)]
+#![recursion_limit="128"]
+extern crate proc_macro;
+#[macro_use]
+extern crate quote;
+#[macro_use]
+extern crate syn;
+
+use self::proc_macro::TokenStream;
+use self::syn::fold::Fold;
+
+struct RecursiveDescentFn {
+}
+
+impl Fold for RecursiveDescentFn {
+  fn fold_item_fn(&mut self, mut i: syn::ItemFn) -> syn::ItemFn {
+    let box block = i.block;
+    let ref ident = i.ident;
+
+    let new_block: syn::Block = parse_quote! {
+      {
+        let next_token_before_parse = self.token_handler.peek();
+        let record = ParseRecord {
+          production_name: stringify!(#ident).to_string(),
+          next_token: format!("{}", next_token_before_parse.to_string_with_metadata()),
+          level: self.parse_level,
+        };
+        self.parse_level += 1;
+        self.parse_record.push(record);
+        let result = { #block };
+
+        if self.parse_level != 0 {
+          self.parse_level -= 1;
+        }
+        result
+      }
+    };
+    i.block = Box::new(new_block);
+    i
+  }
+}
+
+#[proc_macro_attribute]
+pub fn recursive_descent_method(_attr: TokenStream, item: TokenStream) -> TokenStream {
+
+  let input: syn::ItemFn = parse_macro_input!(item as syn::ItemFn);
+  let mut folder = RecursiveDescentFn {};
+  let output = folder.fold_item_fn(input);
+  TokenStream::from(quote!(#output))
+}

schala-lang/language/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "schala-lang"
+version = "0.1.0"
+authors = ["greg <greg.shuflin@protonmail.com>"]
+edition = "2018"
+
+[dependencies]
+itertools = "0.5.8"
+take_mut = "0.1.3"
+maplit = "*"
+lazy_static = "0.2.8"
+failure = "0.1.2"
+ena = "0.11.0"
+stopwatch = "0.0.7"
+
+schala-lang-codegen = { path = "../codegen" }
+schala-repl = { path = "../../schala-repl" }

schala-lang/language/src/ast.rs

@@ -0,0 +1,215 @@
+use std::rc::Rc;
+use std::convert::From;
+
+use crate::builtin::{BinOp, PrefixOp};
+use crate::typechecking::TypeData;
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct Meta<T> {
+  n: T,
+  source_map: SourceMap,
+  type_data: TypeData,
+}
+
+impl<T> Meta<T> {
+  pub fn new(n: T) -> Meta<T> {
+    Meta { n, source_map: SourceMap::default(), type_data: TypeData::new() }
+  }
+
+  pub fn node(&self) -> &T {
+    &self.n
+  }
+}
+
+//TODO this PartialEq is here to make tests work - find a way to make it not necessary
+#[derive(Clone, Debug, Default, PartialEq)]
+struct SourceMap {
+}
+
+impl From<Expression> for Meta<Expression> {
+  fn from(expr: Expression) -> Meta<Expression> {
+    Meta { n: expr, source_map: SourceMap::default(), type_data: TypeData::new() }
+  }
+}
+
+#[derive(Debug, PartialEq)]
+pub struct AST(pub Vec<Meta<Statement>>);
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum Statement {
+  ExpressionStatement(Meta<Expression>),
+  Declaration(Declaration),
+}
+
+pub type Block = Vec<Meta<Statement>>;
+pub type ParamName = Rc<String>;
+pub type FormalParam = (ParamName, Option<TypeIdentifier>);
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum Declaration {
+  FuncSig(Signature),
+  FuncDecl(Signature, Block),
+  TypeDecl {
+    name: TypeSingletonName,
+    body: TypeBody,
+    mutable: bool
+  },
+  TypeAlias(Rc<String>, Rc<String>), //should have TypeSingletonName in it, or maybe just String, not sure
+  Binding {
+    name: Rc<String>,
+    constant: bool,
+    type_anno: Option<TypeIdentifier>,
+    expr: Meta<Expression>,
+  },
+  Impl {
+    type_name: TypeIdentifier,
+    interface_name: Option<TypeSingletonName>,
+    block: Vec<Declaration>,
+  },
+  Interface {
+    name: Rc<String>,
+    signatures: Vec<Signature>
+  }
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub struct Signature {
+  pub name: Rc<String>,
+  pub operator: bool,
+  pub params: Vec<FormalParam>,
+  pub type_anno: Option<TypeIdentifier>,
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub struct TypeBody(pub Vec<Variant>);
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum Variant {
+  UnitStruct(Rc<String>),
+  TupleStruct(Rc<String>, Vec<TypeIdentifier>),
+  Record {
+    name: Rc<String>,
+    members: Vec<(Rc<String>, TypeIdentifier)>,
+  }
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub struct Expression(pub ExpressionKind, pub Option<TypeIdentifier>);
+
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum TypeIdentifier {
+  Tuple(Vec<TypeIdentifier>),
+  Singleton(TypeSingletonName)
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub struct TypeSingletonName {
+  pub name: Rc<String>,
+  pub params: Vec<TypeIdentifier>,
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum ExpressionKind {
+  NatLiteral(u64),
+  FloatLiteral(f64),
+  StringLiteral(Rc<String>),
+  BoolLiteral(bool),
+  BinExp(BinOp, Box<Meta<Expression>>, Box<Meta<Expression>>),
+  PrefixExp(PrefixOp, Box<Meta<Expression>>),
+  TupleLiteral(Vec<Meta<Expression>>),
+  Value(Rc<String>),
+  NamedStruct {
+    name: Rc<String>,
+    fields: Vec<(Rc<String>, Meta<Expression>)>,
+  },
+  Call {
+    f: Box<Meta<Expression>>,
+    arguments: Vec<Meta<Expression>>,
+  },
+  Index {
+    indexee: Box<Meta<Expression>>,
+    indexers: Vec<Meta<Expression>>,
+  },
+  IfExpression {
+    discriminator: Box<Discriminator>,
+    body: Box<IfExpressionBody>,
+  },
+  WhileExpression {
+    condition: Option<Box<Meta<Expression>>>,
+    body: Block,
+  },
+  ForExpression {
+    enumerators: Vec<Enumerator>,
+    body: Box<ForBody>,
+  },
+  Lambda {
+    params: Vec<FormalParam>,
+    type_anno: Option<TypeIdentifier>,
+    body: Block,
+  },
+  ListLiteral(Vec<Meta<Expression>>),
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum Discriminator {
+  Simple(Expression),
+  BinOp(Expression, BinOp)
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum IfExpressionBody {
+  SimpleConditional(Block, Option<Block>),
+  SimplePatternMatch(Pattern, Block, Option<Block>),
+  GuardList(Vec<GuardArm>)
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub struct GuardArm {
+  pub guard: Guard,
+  pub body: Block,
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum Guard {
+  Pat(Pattern),
+  HalfExpr(HalfExpr)
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub struct HalfExpr {
+  pub op: Option<BinOp>,
+  pub expr: ExpressionKind,
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum Pattern {
+  Ignored,
+  TuplePattern(Vec<Pattern>),
+  Literal(PatternLiteral),
+  TupleStruct(Rc<String>, Vec<Pattern>),
+  Record(Rc<String>, Vec<(Rc<String>, Pattern)>),
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum PatternLiteral {
+  NumPattern {
+    neg: bool,
+    num: ExpressionKind,
+  },
+  StringPattern(Rc<String>),
+  BoolPattern(bool),
+  VarPattern(Rc<String>)
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub struct Enumerator {
+  pub id: Rc<String>,
+  pub generator: Meta<Expression>,
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum ForBody {
+  MonadicReturn(Meta<Expression>),
+  StatementBlock(Block),
+}

schala-lang/language/src/builtin.rs

@@ -0,0 +1,122 @@
+use std::rc::Rc;
+use std::collections::HashMap;
+
+use crate::tokenizing::TokenKind;
+use crate::typechecking::{TypeConst, Type};
+
+#[derive(Debug, PartialEq, Clone)]
+pub struct BinOp {
+  sigil: Rc<String>
+}
+
+impl BinOp {
+  pub fn from_sigil(sigil: &str) -> BinOp {
+    BinOp { sigil: Rc::new(sigil.to_string()) }
+  }
+  pub fn sigil(&self) -> &Rc<String> {
+    &self.sigil
+  }
+  pub fn from_sigil_token(tok: &TokenKind) -> Option<BinOp> {
+    use self::TokenKind::*;
+    let s = match tok {
+      Operator(op) => op,
+      Period => ".",
+      Pipe => "|",
+      Slash => "/",
+      LAngleBracket => "<",
+      RAngleBracket => ">",
+      _ => return None
+    };
+    Some(BinOp::from_sigil(s))
+  }
+
+  pub fn get_type(&self) -> Result<Type, String> {
+    let s = self.sigil.as_str();
+    BINOPS.get(s).map(|x| x.0.clone()).ok_or(format!("Binop {} not found", s))
+  }
+
+  pub fn min_precedence() -> i32 {
+    i32::min_value()
+  }
+  pub fn get_precedence_from_token(op: &TokenKind) -> Option<i32> {
+    use self::TokenKind::*;
+    let s = match op {
+      Operator(op) => op,
+      Period => ".",
+      Pipe => "|",
+      Slash => "/",
+      LAngleBracket => "<",
+      RAngleBracket => ">",
+      _ => return None
+    };
+    let default = 10_000_000;
+    Some(BINOPS.get(s).map(|x| x.2.clone()).unwrap_or_else(|| {
+      default
+    }))
+  }
+
+  pub fn get_precedence(&self) -> i32 {
+    let s: &str = &self.sigil;
+    let default = 10_000_000;
+    BINOPS.get(s).map(|x| x.2.clone()).unwrap_or_else(|| {
+      default
+    })
+  }
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub struct PrefixOp {
+  sigil: Rc<String>
+}
+
+impl PrefixOp {
+  pub fn from_sigil(sigil: &str) -> PrefixOp {
+    PrefixOp { sigil: Rc::new(sigil.to_string()) }
+  }
+  pub fn sigil(&self) -> &Rc<String> {
+    &self.sigil
+  }
+  pub fn is_prefix(op: &str) -> bool {
+    PREFIX_OPS.get(op).is_some()
+  }
+  pub fn get_type(&self) -> Result<Type, String> {
+    let s = self.sigil.as_str();
+    PREFIX_OPS.get(s).map(|x| x.0.clone()).ok_or(format!("Prefix op {} not found", s))
+  }
+}
+
+
+lazy_static! {
+  static ref PREFIX_OPS: HashMap<&'static str, (Type, ())> = 
+    hashmap! {
+      "+" => (ty!(Nat -> Int), ()),
+      "-" => (ty!(Nat -> Int), ()),
+      "!" => (ty!(Bool -> Bool), ()),
+    };
+}
+
+/* the second tuple member is a placeholder for when I want to make evaluation rules tied to the
+ * binop definition */
+//TODO some of these types are going to have to be adjusted
+lazy_static! {
+  static ref BINOPS: HashMap<&'static str, (Type, (), i32)> =
+    hashmap! {
+      "+" => (ty!(Nat -> Nat -> Nat), (), 10),
+      "-" => (ty!(Nat -> Nat -> Nat), (), 10),
+      "*" => (ty!(Nat -> Nat -> Nat), (), 20),
+      "/" => (ty!(Nat -> Nat -> Float), (), 20),
+      "quot" => (ty!(Nat -> Nat -> Nat), (), 20),
+      "%" => (ty!(Nat -> Nat -> Nat), (), 20),
+      "++" => (ty!(StringT -> StringT -> StringT), (), 30),
+      "^" => (ty!(Nat -> Nat -> Nat), (), 20),
+      "&" => (ty!(Nat -> Nat -> Nat), (), 20),
+      "|" => (ty!(Nat -> Nat -> Nat), (), 20),
+      ">" => (ty!(Nat -> Nat -> Bool), (), 20),
+      ">=" => (ty!(Nat -> Nat -> Bool), (), 20),
+      "<" => (ty!(Nat -> Nat -> Bool), (), 20),
+      "<=" => (ty!(Nat -> Nat -> Bool), (), 20),
+      "==" => (ty!(Nat -> Nat -> Bool), (), 20),
+      "=" => (ty!(Unit), (), 20), //TODO not sure what the type of this should be b/c special fmr
+      "<=>" => (ty!(Nat -> Nat -> Ordering), (), 20), //TODO figure out how to treat Order
+    };
+}

schala-lang/language/src/eval.rs

@@ -0,0 +1,747 @@
+
+use std::cell::RefCell;
+use std::rc::Rc;
+use std::fmt::Write;
+use std::io;
+
+use itertools::Itertools;
+
+use crate::util::ScopeStack;
+use crate::reduced_ast::{BoundVars, ReducedAST, Stmt, Expr, Lit, Func, Alternative, Subpattern};
+use crate::symbol_table::{SymbolSpec, Symbol, SymbolTable};
+
+pub struct State<'a> {
+  values: ScopeStack<'a, Rc<String>, ValueEntry>,
+  symbol_table_handle: Rc<RefCell<SymbolTable>>,
+}
+
+macro_rules! builtin_binding {
+  ($name:expr, $values:expr) => {
+    $values.insert(Rc::new(format!($name)), ValueEntry::Binding { constant: true, val: Node::Expr(Expr::Func(Func::BuiltIn(Rc::new(format!($name))))) });
+  }
+}
+
+impl<'a> State<'a> {
+  pub fn new(symbol_table_handle: Rc<RefCell<SymbolTable>>) -> State<'a> {
+    let mut values = ScopeStack::new(Some(format!("global")));
+    builtin_binding!("print", values);
+    builtin_binding!("println", values);
+    builtin_binding!("getline", values);
+    State { values, symbol_table_handle }
+  }
+
+  pub fn debug_print(&self) -> String {
+    format!("Values: {:?}", self.values)
+  }
+
+  fn new_frame(&'a self, items: &'a Vec<Node>, bound_vars: &BoundVars) -> State<'a> {
+    let mut inner_state = State {
+      values: self.values.new_scope(None),
+      symbol_table_handle: self.symbol_table_handle.clone(),
+    };
+    for (bound_var, val) in bound_vars.iter().zip(items.iter()) {
+      if let Some(bv) = bound_var.as_ref() {
+        inner_state.values.insert(bv.clone(), ValueEntry::Binding { constant: true, val: val.clone() });
+      }
+    }
+    inner_state
+  }
+}
+
+#[derive(Debug, Clone)]
+enum Node {
+  Expr(Expr),
+  PrimObject {
+    name: Rc<String>,
+    tag: usize,
+    items: Vec<Node>,
+  },
+  PrimTuple {
+    items: Vec<Node>
+  }
+}
+
+fn paren_wrapped_vec(terms: impl Iterator<Item=String>) -> String {
+  let mut buf = String::new();
+  write!(buf, "(").unwrap();
+  for term in terms.map(|e| Some(e)).intersperse(None) {
+    match term {
+      Some(e) => write!(buf, "{}", e).unwrap(),
+      None => write!(buf, ", ").unwrap(),
+    };
+  }
+  write!(buf, ")").unwrap();
+  buf
+}
+
+
+impl Node {
+  fn to_repl(&self) -> String {
+    match self {
+      Node::Expr(e) => e.to_repl(),
+      Node::PrimObject { name, items, .. } if items.len() == 0 => format!("{}", name),
+      Node::PrimObject { name, items, .. } => format!("{}{}", name, paren_wrapped_vec(items.iter().map(|x| x.to_repl()))),
+      Node::PrimTuple { items } => format!("{}", paren_wrapped_vec(items.iter().map(|x| x.to_repl()))),
+    }
+  }
+  fn is_true(&self) -> bool {
+    match self {
+      Node::Expr(Expr::Lit(crate::reduced_ast::Lit::Bool(true))) => true,
+      _ => false,
+    }
+  }
+}
+
+#[derive(Debug)]
+enum ValueEntry {
+  Binding {
+    constant: bool,
+    val: /*FullyEvaluatedExpr*/ Node, //TODO make this use a subtype to represent fully evaluatedness
+  }
+}
+
+type EvalResult<T> = Result<T, String>;
+
+impl Expr {
+  fn to_node(self) -> Node {
+    Node::Expr(self)
+  }
+  fn to_repl(&self) -> String {
+    use self::Lit::*;
+    use self::Func::*;
+
+    match self {
+      Expr::Lit(ref l) => match l {
+        Nat(n) => format!("{}", n),
+        Int(i) => format!("{}", i),
+        Float(f) => format!("{}", f),
+        Bool(b) => format!("{}", b),
+        StringLit(s) => format!("\"{}\"", s),
+      },
+      Expr::Func(f) => match f {
+        BuiltIn(name) => format!("<built-in function '{}'>", name),
+        UserDefined { name: None, .. } => format!("<function>"),
+        UserDefined { name: Some(name), .. } => format!("<function '{}'>", name),
+      },
+      Expr::Constructor { 
+        type_name: _, name, arity, ..
+      } => if *arity == 0 {
+        format!("{}", name)
+      } else {
+        format!("<data constructor '{}'>", name)
+      },
+      Expr::Tuple(exprs) => paren_wrapped_vec(exprs.iter().map(|x| x.to_repl())),
+      _ => format!("{:?}", self),
+    }
+  }
+
+  fn replace_conditional_target_sigil(self, replacement: &Expr) -> Expr {
+    use self::Expr::*;
+
+    match self {
+      ConditionalTargetSigilValue => replacement.clone(),
+      Unit | Lit(_) | Func(_) | Val(_) | Constructor { .. } |
+       CaseMatch { .. } | UnimplementedSigilValue => self,
+      Tuple(exprs) => Tuple(exprs.into_iter().map(|e| e.replace_conditional_target_sigil(replacement)).collect()),
+      Call { f, args } => {
+        let new_args = args.into_iter().map(|e| e.replace_conditional_target_sigil(replacement)).collect();
+        Call { f, args: new_args }
+      },
+      Conditional { .. } => panic!("Dunno if I need this, but if so implement"),
+      Assign { .. } => panic!("I'm pretty sure I don't need this"),
+    }
+  }
+}
+
+impl<'a> State<'a> {
+  pub fn evaluate(&mut self, ast: ReducedAST, repl: bool) -> Vec<Result<String, String>> {
+    let mut acc = vec![];
+
+    // handle prebindings
+    for statement in ast.0.iter() {
+      self.prebinding(statement);
+    }
+
+    for statement in ast.0 {
+      match self.statement(statement) {
+        Ok(Some(ref output)) if repl => acc.push(Ok(output.to_repl())),
+        Ok(_) => (),
+        Err(error) => {
+          acc.push(Err(format!("Runtime error: {}", error)));
+          return acc;
+        },
+      }
+    }
+    acc
+  }
+
+  fn prebinding(&mut self, stmt: &Stmt) {
+    match stmt {
+      Stmt::PreBinding { name, func } => {
+        let v_entry = ValueEntry::Binding { constant: true, val: Node::Expr(Expr::Func(func.clone())) };
+        self.values.insert(name.clone(), v_entry);
+      },
+      Stmt::Expr(_expr) => {
+        //TODO have this support things like nested function defs
+
+      },
+      _ => ()
+    }
+  }
+
+  fn statement(&mut self, stmt: Stmt) -> EvalResult<Option<Node>> {
+    match stmt {
+      Stmt::Binding { name, constant, expr } => {
+        let val = self.expression(Node::Expr(expr))?;
+        self.values.insert(name.clone(), ValueEntry::Binding { constant, val });
+        Ok(None)
+      },
+      Stmt::Expr(expr) => Ok(Some(self.expression(expr.to_node())?)),
+      Stmt::PreBinding {..} | Stmt::Noop => Ok(None),
+    }
+  }
+
+  fn block(&mut self, stmts: Vec<Stmt>) -> EvalResult<Node> {
+    let mut ret = None;
+    for stmt in stmts {
+      ret = self.statement(stmt)?;
+    }
+    Ok(ret.unwrap_or(Node::Expr(Expr::Unit)))
+  }
+
+  fn expression(&mut self, node: Node) -> EvalResult<Node> {
+    use self::Expr::*;
+    match node {
+      t @ Node::PrimTuple { .. } => Ok(t),
+      obj @ Node::PrimObject { .. } =>  Ok(obj),
+      Node::Expr(expr) => match expr {
+        literal @ Lit(_) => Ok(Node::Expr(literal)),
+        Call { box f, args } => self.call_expression(f, args),
+        Val(v) => self.value(v),
+        Constructor { arity, ref name, tag, .. } if arity == 0 => Ok(Node::PrimObject { name: name.clone(), tag, items: vec![] }),
+        constructor @ Constructor { .. } => Ok(Node::Expr(constructor)),
+        func @ Func(_) => Ok(Node::Expr(func)),
+        Tuple(exprs) => {
+          let nodes = exprs.into_iter().map(|expr| self.expression(Node::Expr(expr))).collect::<Result<Vec<Node>,_>>()?;
+          Ok(Node::PrimTuple { items: nodes })
+        },
+        Conditional { box cond, then_clause, else_clause } => self.conditional(cond, then_clause, else_clause),
+        Assign { box val, box expr } => self.assign_expression(val, expr),
+        Unit => Ok(Node::Expr(Unit)),
+        CaseMatch { box cond, alternatives } => self.case_match_expression(cond, alternatives),
+        ConditionalTargetSigilValue => Ok(Node::Expr(ConditionalTargetSigilValue)),
+        UnimplementedSigilValue => Err(format!("Sigil value eval not implemented")),
+      }
+    }
+  }
+
+  fn call_expression(&mut self, f: Expr, args: Vec<Expr>) -> EvalResult<Node> {
+    use self::Expr::*;
+    match self.expression(Node::Expr(f))? {
+      Node::Expr(Constructor { type_name, name, tag, arity }) => self.apply_data_constructor(type_name, name, tag, arity, args),
+      Node::Expr(Func(f)) => self.apply_function(f, args),
+      other => return Err(format!("Tried to call {:?} which is not a function or data constructor", other)),
+    }
+  }
+
+  fn apply_data_constructor(&mut self, _type_name: Rc<String>, name: Rc<String>, tag: usize, arity: usize, args: Vec<Expr>) -> EvalResult<Node> {
+    if arity != args.len() {
+      return Err(format!("Data constructor {} requires {} args", name, arity));
+    }
+
+    let evaled_args = args.into_iter().map(|expr| self.expression(Node::Expr(expr))).collect::<Result<Vec<Node>,_>>()?;
+    //let evaled_args = vec![];
+    Ok(Node::PrimObject {
+      name: name.clone(),
+      items: evaled_args,
+      tag 
+    })
+  }
+
+  fn apply_function(&mut self, f: Func, args: Vec<Expr>) -> EvalResult<Node> {
+    match f {
+      Func::BuiltIn(sigil) => Ok(Node::Expr(self.apply_builtin(sigil, args)?)),
+      Func::UserDefined { params, body, name } => {
+
+        if params.len() != args.len() {
+          return Err(format!("calling a {}-argument function with {} args", params.len(), args.len()))
+        }
+        let mut func_state = State {
+          values: self.values.new_scope(name.map(|n| format!("{}", n))),
+          symbol_table_handle: self.symbol_table_handle.clone(),
+        };
+        for (param, val) in params.into_iter().zip(args.into_iter()) {
+          let val = func_state.expression(Node::Expr(val))?;
+          func_state.values.insert(param, ValueEntry::Binding { constant: true, val });
+        }
+        // TODO figure out function return semantics
+        func_state.block(body)
+      }
+    }
+  }
+
+  fn apply_builtin(&mut self, name: Rc<String>, args: Vec<Expr>) -> EvalResult<Expr> {
+    use self::Expr::*;
+    use self::Lit::*;
+    let evaled_args: Result<Vec<Expr>, String> = args.into_iter().map(|arg| {
+      match self.expression(Node::Expr(arg)) {
+        Ok(Node::Expr(e)) => Ok(e),
+        Ok(Node::PrimTuple { .. }) => Err(format!("Trying to apply a builtin to a tuple")),
+        Ok(Node::PrimObject { .. }) => Err(format!("Trying to apply a builtin to a primitive object")),
+        Err(e) => Err(e)
+      }
+    }).collect();
+    let evaled_args = evaled_args?;
+
+    Ok(match (name.as_str(), evaled_args.as_slice()) {
+      /* binops */
+      ("+", &[Lit(Nat(l)), Lit(Nat(r))]) => Lit(Nat(l + r)),
+      ("++", &[Lit(StringLit(ref s1)), Lit(StringLit(ref s2))]) => Lit(StringLit(Rc::new(format!("{}{}", s1, s2)))),
+      ("-", &[Lit(Nat(l)), Lit(Nat(r))]) => Lit(Nat(l - r)),
+      ("*", &[Lit(Nat(l)), Lit(Nat(r))]) => Lit(Nat(l * r)),
+      ("/", &[Lit(Nat(l)), Lit(Nat(r))]) => Lit(Float((l as f64)/ (r as f64))),
+      ("quot", &[Lit(Nat(l)), Lit(Nat(r))]) => if r == 0 {
+        return Err(format!("divide by zero"));
+      } else {
+        Lit(Nat(l / r))
+      },
+      ("%", &[Lit(Nat(l)), Lit(Nat(r))]) => Lit(Nat(l % r)),
+      ("^", &[Lit(Nat(l)), Lit(Nat(r))]) => Lit(Nat(l ^ r)),
+      ("&", &[Lit(Nat(l)), Lit(Nat(r))]) => Lit(Nat(l & r)),
+      ("|", &[Lit(Nat(l)), Lit(Nat(r))]) => Lit(Nat(l | r)),
+
+      /* comparisons */
+      ("==", &[Lit(Nat(l)), Lit(Nat(r))]) => Lit(Bool(l == r)),
+      ("==", &[Lit(Int(l)), Lit(Int(r))]) => Lit(Bool(l == r)),
+      ("==", &[Lit(Float(l)), Lit(Float(r))]) => Lit(Bool(l == r)),
+      ("==", &[Lit(Bool(l)), Lit(Bool(r))]) => Lit(Bool(l == r)),
+      ("==", &[Lit(StringLit(ref l)), Lit(StringLit(ref r))]) => Lit(Bool(l == r)),
+
+      ("<", &[Lit(Nat(l)), Lit(Nat(r))]) => Lit(Bool(l < r)),
+      ("<", &[Lit(Int(l)), Lit(Int(r))]) => Lit(Bool(l < r)),
+      ("<", &[Lit(Float(l)), Lit(Float(r))]) => Lit(Bool(l < r)),
+
+      ("<=", &[Lit(Nat(l)), Lit(Nat(r))]) => Lit(Bool(l <= r)),
+      ("<=", &[Lit(Int(l)), Lit(Int(r))]) => Lit(Bool(l <= r)),
+      ("<=", &[Lit(Float(l)), Lit(Float(r))]) => Lit(Bool(l <= r)),
+
+      (">", &[Lit(Nat(l)), Lit(Nat(r))]) => Lit(Bool(l > r)),
+      (">", &[Lit(Int(l)), Lit(Int(r))]) => Lit(Bool(l > r)),
+      (">", &[Lit(Float(l)), Lit(Float(r))]) => Lit(Bool(l > r)),
+
+      (">=", &[Lit(Nat(l)), Lit(Nat(r))]) => Lit(Bool(l >= r)),
+      (">=", &[Lit(Int(l)), Lit(Int(r))]) => Lit(Bool(l >= r)),
+      (">=", &[Lit(Float(l)), Lit(Float(r))]) => Lit(Bool(l >= r)),
+
+      /* prefix ops */
+      ("!", &[Lit(Bool(true))]) => Lit(Bool(false)),
+      ("!", &[Lit(Bool(false))]) => Lit(Bool(true)),
+      ("-", &[Lit(Nat(n))]) => Lit(Int(-1*(n as i64))),
+      ("-", &[Lit(Int(n))]) => Lit(Int(-1*(n as i64))),
+      ("+", &[Lit(Int(n))]) => Lit(Int(n)),
+      ("+", &[Lit(Nat(n))]) => Lit(Nat(n)),
+
+
+      /* builtin functions */
+      ("print", &[ref anything]) => {
+        print!("{}", anything.to_repl());
+        Expr::Unit
+      },
+      ("println", &[ref anything]) => {
+        println!("{}", anything.to_repl());
+        Expr::Unit
+      },
+      ("getline", &[]) => {
+        let mut buf = String::new();
+        io::stdin().read_line(&mut buf).expect("Error readling line in 'getline'");
+        Lit(StringLit(Rc::new(buf.trim().to_string())))
+      },
+      (x, args) => return Err(format!("bad or unimplemented builtin {:?} | {:?}", x, args)),
+    })
+  }
+
+  fn conditional(&mut self, cond: Expr, then_clause: Vec<Stmt>, else_clause: Vec<Stmt>) -> EvalResult<Node> {
+    let cond = self.expression(Node::Expr(cond))?;
+    Ok(match cond {
+      Node::Expr(Expr::Lit(Lit::Bool(true))) =>  self.block(then_clause)?,
+      Node::Expr(Expr::Lit(Lit::Bool(false))) => self.block(else_clause)?,
+      _ => return Err(format!("Conditional with non-boolean condition"))
+    })
+  }
+
+  fn assign_expression(&mut self, val: Expr, expr: Expr) -> EvalResult<Node> {
+    let name = match val  {
+      Expr::Val(name) => name,
+      _ => return Err(format!("Trying to assign to a non-value")),
+    };
+
+    let constant = match self.values.lookup(&name) {
+      None => return Err(format!("Constant {} is undefined", name)),
+      Some(ValueEntry::Binding { constant, .. }) => constant.clone(),
+    };
+    if constant {
+      return Err(format!("trying to update {}, a non-mutable binding", name));
+    }
+    let val = self.expression(Node::Expr(expr))?;
+    self.values.insert(name.clone(), ValueEntry::Binding { constant: false, val });
+    Ok(Node::Expr(Expr::Unit))
+  }
+
+  fn guard_passes(&mut self, guard: &Option<Expr>, cond: &Node) -> EvalResult<bool> {
+    if let Some(ref guard_expr) = guard {
+      let guard_expr = match cond {
+        Node::Expr(ref e) => guard_expr.clone().replace_conditional_target_sigil(e),
+        _ => guard_expr.clone()
+      };
+      Ok(self.expression(guard_expr.to_node())?.is_true())
+    } else {
+      Ok(true)
+    }
+  }
+
+  fn case_match_expression(&mut self, cond: Expr, alternatives: Vec<Alternative>) -> EvalResult<Node> {
+
+    //TODO need to handle recursive subpatterns
+    let all_subpatterns_pass = |state: &mut State, subpatterns: &Vec<Option<Subpattern>>, items: &Vec<Node>| -> EvalResult<bool> {
+
+      if subpatterns.len() == 0 {
+        return Ok(true)
+      }
+
+      if items.len() != subpatterns.len() {
+        return Err(format!("Subpattern length isn't correct items {} subpatterns {}", items.len(), subpatterns.len()));
+      }
+
+      for (maybe_subp, cond) in subpatterns.iter().zip(items.iter()) {
+        if let Some(subp) = maybe_subp {
+          if !state.guard_passes(&subp.guard, &cond)? {
+            return Ok(false)
+          }
+        }
+      }
+      Ok(true)
+    };
+
+    let cond = self.expression(Node::Expr(cond))?;
+    for alt in alternatives {
+      // no matter what type of condition we have, ignore alternative if the guard evaluates false
+      if !self.guard_passes(&alt.guard, &cond)? {
+        continue;
+      }
+
+      match cond {
+        Node::PrimObject { ref tag, ref items, .. } => {
+          if alt.tag.map(|t| t == *tag).unwrap_or(true) {
+            let mut inner_state = self.new_frame(items, &alt.bound_vars);
+            if all_subpatterns_pass(&mut inner_state, &alt.subpatterns, items)? {
+              return inner_state.block(alt.item);
+            } else {
+              continue;
+            }
+          }
+        },
+        Node::PrimTuple { ref items } =>  {
+          let mut inner_state = self.new_frame(items, &alt.bound_vars);
+          if all_subpatterns_pass(&mut inner_state, &alt.subpatterns, items)? {
+            return inner_state.block(alt.item);
+          } else {
+            continue;
+          }
+        },
+        Node::Expr(ref _e) => {
+          if let None = alt.tag {
+            return self.block(alt.item)
+          }
+        }
+      }
+    }
+    Err(format!("{:?} failed pattern match", cond))
+  }
+
+  //TODO if I don't need to lookup by name here...
+  fn value(&mut self, name: Rc<String>) -> EvalResult<Node> {
+    use self::ValueEntry::*;
+    use self::Func::*;
+    //TODO add a layer of indirection here to talk to the symbol table first, and only then look up
+    //in the values table
+
+    let symbol_table = self.symbol_table_handle.borrow();
+    let value = symbol_table.lookup_by_name(&name);
+    Ok(match value {
+      Some(Symbol { name, spec, .. }) => match spec {
+        //TODO I'll need this type_name later to do a table lookup
+        SymbolSpec::DataConstructor { type_name: _type_name, type_args, .. } => {
+          if type_args.len() == 0 {
+            Node::PrimObject { name: name.clone(), tag: 0, items: vec![] }
+          } else {
+            return Err(format!("This data constructor thing not done"))
+          }
+        },
+        SymbolSpec::Func(_) => match self.values.lookup(&name) {
+          Some(Binding { val: Node::Expr(Expr::Func(UserDefined { name, params, body })), .. }) => {
+            Node::Expr(Expr::Func(UserDefined { name: name.clone(), params: params.clone(), body: body.clone() }))
+          },
+          _ => unreachable!(),
+        },
+        SymbolSpec::RecordConstructor { .. } => return Err(format!("This shouldn't be a record!")),
+        SymbolSpec::Binding => match self.values.lookup(&name) {
+          Some(Binding { val, .. }) => val.clone(),
+          None => return Err(format!("Symbol {} exists in symbol table but not in evaluator table", name))
+        }
+      },
+      //TODO ideally this should be returning a runtime error if this is ever None, but it's not
+      //handling all bindings correctly yet
+      //None => return Err(format!("Couldn't find value {}", name)),
+      None => match self.values.lookup(&name) {
+        Some(Binding { val, .. }) => val.clone(),
+        None => return Err(format!("Couldn't find value {}", name)),
+      }
+    })
+  }
+}
+
+#[cfg(test)]
+mod eval_tests {
+  use std::cell::RefCell;
+  use std::rc::Rc;
+
+  use crate::symbol_table::SymbolTable;
+  use crate::eval::State;
+
+  fn evaluate_all_outputs(input: &str) -> Vec<Result<String, String>> {
+    let symbol_table = Rc::new(RefCell::new(SymbolTable::new()));
+    let mut state = State::new(symbol_table);
+    let ast = crate::util::quick_ast(input);
+    state.symbol_table_handle.borrow_mut().add_top_level_symbols(&ast).unwrap();
+    let reduced = ast.reduce(&state.symbol_table_handle.borrow());
+    let all_output = state.evaluate(reduced, true);
+    all_output
+  }
+
+  macro_rules! test_in_fresh_env {
+    ($string:expr, $correct:expr) => {
+      {
+        let all_output = evaluate_all_outputs($string);
+        let ref output = all_output.last().unwrap();
+        assert_eq!(**output, Ok($correct.to_string()));
+      }
+    }
+  }
+
+  #[test]
+  fn test_basic_eval() {
+    test_in_fresh_env!("1 + 2", "3");
+    test_in_fresh_env!("let mut a = 1; a = 2", "Unit");
+    test_in_fresh_env!("let mut a = 1; a = 2; a", "2");
+    test_in_fresh_env!(r#"("a", 1 + 2)"#, r#"("a", 3)"#);
+  }
+
+  #[test]
+  fn function_eval() {
+    test_in_fresh_env!("fn oi(x) { x + 1 }; oi(4)", "5");
+    test_in_fresh_env!("fn oi(x) { x + 1 }; oi(1+2)", "4");
+  }
+
+  #[test]
+  fn scopes() {
+    let scope_ok = r#"
+    let a = 20
+    fn haha() {
+      let a = 10
+      a
+    }
+    haha()
+    "#;
+    test_in_fresh_env!(scope_ok, "10");
+    let scope_ok = r#"
+    let a = 20
+    fn haha() {
+      let a = 10
+      a
+    }
+    a
+    "#;
+    test_in_fresh_env!(scope_ok, "20");
+  }
+
+  #[test]
+  fn if_is_patterns() {
+    let source = r#"
+type Option<T> = Some(T) | None
+let x = Some(9); if x is Some(q) then { q } else { 0 }"#;
+    test_in_fresh_env!(source, "9");
+
+    let source = r#"
+type Option<T> = Some(T) | None
+let x = None; if x is Some(q) then { q } else { 0 }"#;
+    test_in_fresh_env!(source, "0");
+  }
+
+  #[test]
+  fn full_if_matching() {
+    let source = r#"
+type Option<T> = Some(T) | None
+let a = None
+if a { is None -> 4, is Some(x) -> x }
+"#;
+  test_in_fresh_env!(source, "4");
+
+    let source = r#"
+type Option<T> = Some(T) | None
+let a = Some(99)
+if a { is None -> 4, is Some(x) -> x }
+"#;
+  test_in_fresh_env!(source, "99");
+
+  let source = r#"
+let a = 10
+if a { is 10 -> "x", is 4 -> "y" }
+"#;
+  test_in_fresh_env!(source, "\"x\"");
+
+  let source = r#"
+let a = 10
+if a { is 15 -> "x", is 10 -> "y" }
+"#;
+  test_in_fresh_env!(source, "\"y\"");
+  }
+
+  #[test]
+  fn string_pattern() {
+    let source = r#"
+let a = "foo"
+if a { is "foo" -> "x", is _ -> "y" }
+"#;
+    test_in_fresh_env!(source, "\"x\"");
+  }
+
+  #[test]
+  fn boolean_pattern() {
+    let source = r#"
+let a = true
+if a { 
+  is true -> "x",
+  is false -> "y"
+}
+"#;
+    test_in_fresh_env!(source, "\"x\"");
+  }
+
+  #[test]
+  fn boolean_pattern_2() {
+    let source = r#"
+let a = false
+if a { is true -> "x", is false -> "y" }
+"#;
+    test_in_fresh_env!(source, "\"y\"");
+  }
+
+  #[test]
+  fn ignore_pattern() {
+    let source = r#"
+type Option<T> = Some(T) | None
+if Some(10) {
+  is _ -> "hella"
+}
+"#;
+    test_in_fresh_env!(source, "\"hella\"");
+  }
+
+  #[test]
+  fn tuple_pattern() {
+    let source = r#"
+if (1, 2) {
+  is (1, x) -> x,
+  is _ -> 99
+}
+"#;
+    test_in_fresh_env!(source, 2);
+  }
+
+
+  #[test]
+  fn tuple_pattern_2() {
+    let source = r#"
+if (1, 2) {
+  is (10, x) -> x,
+  is (y, x) -> x + y
+}
+"#;
+    test_in_fresh_env!(source, 3);
+  }
+
+  #[test]
+  fn tuple_pattern_3() {
+    let source = r#"
+if (1, 5) {
+  is (10, x) -> x,
+  is (1, x) -> x
+}
+"#;
+    test_in_fresh_env!(source, 5);
+  }
+
+  #[test]
+  fn tuple_pattern_4() {
+    let source = r#"
+if (1, 5) {
+  is (10, x) -> x,
+  is (1, x) -> x,
+}
+"#;
+    test_in_fresh_env!(source, 5);
+  }
+
+  #[test]
+  fn  prim_obj_pattern() {
+    let source = r#"
+type Stuff = Mulch(Nat) | Jugs(Nat, String) | Mardok
+let a = Mulch(20)
+let b = Jugs(1, "haha")
+let c = Mardok
+
+let x = if a {
+  is Mulch(20) -> "x",
+  is _ -> "ERR"
+}
+
+let y = if b {
+  is Mulch(n) -> "ERR",
+  is Jugs(2, _) -> "ERR",
+  is Jugs(1, s) -> s,
+  is _ -> "ERR",
+}
+
+let z = if c {
+  is Jugs(_, _) -> "ERR",
+  is Mardok -> "NIGH",
+  is _ -> "ERR",
+}
+
+(x, y, z)
+"#;
+  test_in_fresh_env!(source, r#"("x", "haha", "NIGH")"#);
+  }
+
+  #[test]
+  fn basic_lambda_syntax() {
+    let source = r#"
+let q = \(x, y) { x * y }
+let x = q(5,2)
+let y = \(m, n, o) { m + n + o }(1,2,3)
+(x, y)
+  "#;
+  test_in_fresh_env!(source, r"(10, 6)");
+  }
+
+  #[test]
+  fn lambda_syntax_2() {
+    let source = r#"
+fn milta() {
+  \(x) { x + 33 }
+}
+milta()(10)
+  "#;
+    test_in_fresh_env!(source, "43");
+  }
+}

schala-lang/language/src/lib.rs

@@ -0,0 +1,332 @@
+#![feature(trace_macros)]
+#![feature(custom_attribute)]
+//#![feature(unrestricted_attribute_tokens)]
+#![feature(slice_patterns, box_patterns, box_syntax)]
+
+//! `schala-lang` is where the Schala programming language is actually implemented. 
+//! It defines the `Schala` type, which contains the state for a Schala REPL, and implements
+//! `ProgrammingLanguageInterface` and the chain of compiler passes for it.
+
+extern crate itertools;
+#[macro_use]
+extern crate lazy_static;
+#[macro_use]
+extern crate maplit;
+extern crate schala_repl;
+#[macro_use]
+extern crate schala_lang_codegen;
+extern crate ena;
+
+use stopwatch::Stopwatch;
+
+use std::time::Duration;
+use std::cell::RefCell;
+use std::rc::Rc;
+use std::collections::HashSet;
+
+use itertools::Itertools;
+use schala_repl::{ProgrammingLanguageInterface,
+ComputationRequest, ComputationResponse,
+LangMetaRequest, LangMetaResponse, GlobalOutputStats,
+DebugResponse, DebugAsk};
+
+macro_rules! bx {
+  ($e:expr) => { Box::new($e) }
+}
+
+#[macro_use]
+mod util;
+#[macro_use]
+mod typechecking;
+
+mod tokenizing;
+mod ast;
+mod parsing;
+mod symbol_table;
+mod builtin;
+mod reduced_ast;
+mod eval;
+
+/// All bits of state necessary to parse and execute a Schala program are stored in this struct.
+/// `state` represents the execution state for the AST-walking interpreter, the other fields
+/// should be self-explanatory.
+pub struct Schala {
+  source_reference: SourceReference,
+  state: eval::State<'static>,
+  symbol_table: Rc<RefCell<symbol_table::SymbolTable>>,
+  type_context: typechecking::TypeContext<'static>,
+  active_parser: Option<parsing::Parser>,
+}
+
+impl Schala {
+  fn handle_docs(&self, source: String) -> LangMetaResponse {
+    LangMetaResponse::Docs {
+      doc_string: format!("Schala item `{}` : <<Schala-lang documentation not yet implemented>>", source)
+    }
+  }
+}
+
+impl Schala {
+  /// Creates a new Schala environment *without* any prelude.
+  fn new_blank_env() -> Schala {
+    let symbols = Rc::new(RefCell::new(symbol_table::SymbolTable::new()));
+    Schala {
+      source_reference: SourceReference::new(),
+      symbol_table: symbols.clone(),
+      state: eval::State::new(symbols),
+      type_context: typechecking::TypeContext::new(),
+      active_parser: None,
+    }
+  }
+
+  /// Creates a new Schala environment with the standard prelude, which is defined as ordinary
+  /// Schala code in the file `prelude.schala`
+  pub fn new() -> Schala {
+    let prelude = include_str!("prelude.schala");
+    let mut s = Schala::new_blank_env();
+
+    let request = ComputationRequest { source: prelude, debug_requests: HashSet::default() };
+    s.run_computation(request);
+    s
+  }
+
+  fn handle_debug_immediate(&self, request: DebugAsk) -> DebugResponse {
+    use DebugAsk::*;
+    match request {
+      Timing => DebugResponse { ask: Timing, value: format!("Invalid") },
+      ByStage { stage_name } => match &stage_name[..] {
+        "symbol-table" => {
+          let value = self.symbol_table.borrow().debug_symbol_table();
+          DebugResponse {
+            ask: ByStage { stage_name: format!("symbol-table") },
+            value
+          }
+        },
+        s => {
+          DebugResponse {
+            ask: ByStage { stage_name: s.to_string() },
+            value: format!("Not-implemented")
+          }
+        }
+      }
+    }
+  }
+}
+
+fn tokenizing(input: &str, _handle: &mut Schala, comp: Option<&mut PassDebugArtifact>) -> Result<Vec<tokenizing::Token>, String> {
+  let tokens = tokenizing::tokenize(input);
+  comp.map(|comp| {
+    let token_string = tokens.iter().map(|t| t.to_string_with_metadata()).join(", ");
+    comp.add_artifact(token_string);
+  });
+
+  let errors: Vec<String> = tokens.iter().filter_map(|t| t.get_error()).collect();
+  if errors.len() == 0 {
+    Ok(tokens)
+  } else {
+    Err(format!("{:?}", errors))
+  }
+}
+
+fn parsing(input: Vec<tokenizing::Token>, handle: &mut Schala, comp: Option<&mut PassDebugArtifact>) -> Result<ast::AST, String> {
+  use crate::parsing::Parser;
+
+  let mut parser = match handle.active_parser.take() {
+    None => Parser::new(input),
+    Some(parser) => parser
+  };
+
+  let ast = parser.parse();
+  let _trace = parser.format_parse_trace();
+
+  comp.map(|_comp| {
+    /*
+    //TODO need to control which of these debug stages get added
+    let opt = comp.cur_debug_options.get(0).map(|s| s.clone());
+    match opt {
+      None => comp.add_artifact(TraceArtifact::new("ast", format!("{:?}", ast))),
+      Some(ref s) if s == "compact" => comp.add_artifact(TraceArtifact::new("ast", format!("{:?}", ast))),
+      Some(ref s) if s == "expanded" => comp.add_artifact(TraceArtifact::new("ast", format!("{:#?}", ast))),
+      Some(ref s) if s == "trace" => comp.add_artifact(TraceArtifact::new_parse_trace(trace)),
+      Some(ref x) => println!("Bad parsing debug option: {}", x),
+    };
+    */
+  });
+  ast.map_err(|err| format_parse_error(err, handle))
+}
+
+fn format_parse_error(error: parsing::ParseError, handle: &mut Schala) -> String {
+  let line_num = error.token.line_num;
+  let ch = error.token.char_num;
+  let line_from_program = handle.source_reference.get_line(line_num);
+  let location_pointer = format!("{}^", " ".repeat(ch));
+
+  let line_num_digits = format!("{}", line_num).chars().count();
+  let space_padding = " ".repeat(line_num_digits);
+
+  format!(r#"
+{error_msg}
+{space_padding} |
+{line_num} | {}
+{space_padding} | {}
+"#, line_from_program, location_pointer, error_msg=error.msg, space_padding=space_padding, line_num=line_num)
+}
+
+fn symbol_table(input: ast::AST, handle: &mut Schala, comp: Option<&mut PassDebugArtifact>) -> Result<ast::AST, String> {
+  let add = handle.symbol_table.borrow_mut().add_top_level_symbols(&input);
+  match add {
+    Ok(()) => {
+      let debug = handle.symbol_table.borrow().debug_symbol_table();
+      comp.map(|comp| comp.add_artifact(debug));
+      Ok(input)
+    },
+    Err(msg) => Err(msg)
+  }
+}
+
+fn typechecking(input: ast::AST, handle: &mut Schala, comp: Option<&mut PassDebugArtifact>) -> Result<ast::AST, String> {
+  let result = handle.type_context.typecheck(&input);
+
+  comp.map(|comp| {
+    comp.add_artifact(match result {
+      Ok(ty) => ty.to_string(),
+      Err(err) => format!("Type error: {}", err.msg)
+    });
+  });
+
+  Ok(input)
+}
+
+fn ast_reducing(input: ast::AST, handle: &mut Schala, comp: Option<&mut PassDebugArtifact>) -> Result<reduced_ast::ReducedAST, String> {
+  let ref symbol_table = handle.symbol_table.borrow();
+  let output = input.reduce(symbol_table);
+  comp.map(|comp| comp.add_artifact(format!("{:?}", output)));
+  Ok(output)
+}
+
+fn eval(input: reduced_ast::ReducedAST, handle: &mut Schala, comp: Option<&mut PassDebugArtifact>) -> Result<String, String> {
+  comp.map(|comp| comp.add_artifact(handle.state.debug_print()));
+  let evaluation_outputs = handle.state.evaluate(input, true);
+  let text_output: Result<Vec<String>, String> = evaluation_outputs
+    .into_iter()
+    .collect();
+
+  let eval_output: Result<String, String> = text_output
+    .map(|v| { v.into_iter().intersperse(format!("\n")).collect() });
+  eval_output
+}
+
+/// Represents lines of source code
+struct SourceReference {
+  lines: Option<Vec<String>>
+}
+
+impl SourceReference {
+  fn new() -> SourceReference {
+    SourceReference { lines: None }
+  }
+
+  fn load_new_source(&mut self, source: &str) {
+    //TODO this is a lot of heap allocations - maybe there's a way to make it more efficient?
+    self.lines = Some(source.lines().map(|s| s.to_string()).collect()); }
+
+  fn get_line(&self, line: usize) -> String {
+    self.lines.as_ref().and_then(|x| x.get(line).map(|s| s.to_string())).unwrap_or(format!("NO LINE FOUND"))
+  }
+}
+
+#[derive(Default)]
+struct PassDebugArtifact {
+  artifacts: Vec<String>
+}
+impl PassDebugArtifact {
+  fn add_artifact(&mut self, artifact: String) {
+    self.artifacts.push(artifact)
+  }
+}
+
+fn stage_names() -> Vec<&'static str> {
+  vec![
+    "tokenizing",
+    "parsing",
+    "symbol-table",
+    "typechecking",
+    "ast-reduction",
+    "ast-walking-evaluation"
+  ]
+}
+
+
+impl ProgrammingLanguageInterface for Schala {
+  fn get_language_name(&self) -> String { format!("Schala") }
+  fn get_source_file_suffix(&self) -> String { format!("schala") }
+
+  fn run_computation(&mut self, request: ComputationRequest) -> ComputationResponse {
+    struct PassToken<'a> {
+      schala: &'a mut Schala,
+      stage_durations: &'a mut Vec<(String, Duration)>,
+      sw: &'a Stopwatch,
+      debug_requests: &'a HashSet<DebugAsk>,
+      debug_responses: &'a mut Vec<DebugResponse>,
+    }
+
+    fn output_wrapper<Input, Output, F>(n: usize, func: F, input: Input, tok: &mut PassToken) -> Result<Output, String>
+      where F: Fn(Input, &mut Schala, Option<&mut PassDebugArtifact>) -> Result<Output, String>
+    {
+      let stage_names = stage_names();
+      let mut debug_artifact = if tok.debug_requests.contains(&DebugAsk::ByStage { stage_name: stage_names[n].to_string() }) {
+        Some(PassDebugArtifact::default())
+      } else {
+        None
+      };
+      let output = func(input, tok.schala, debug_artifact.as_mut());
+      tok.stage_durations.push((stage_names[n].to_string(), tok.sw.elapsed()));
+      if let Some(artifact) = debug_artifact {
+        for value in artifact.artifacts.into_iter() {
+          let resp = DebugResponse {
+            ask: DebugAsk::ByStage { stage_name: stage_names[n].to_string() },
+            value,
+          };
+          tok.debug_responses.push(resp);
+        }
+      }
+      output
+    }
+
+    let ComputationRequest { source, debug_requests } = request;
+    self.source_reference.load_new_source(source);
+    let sw = Stopwatch::start_new();
+    let mut stage_durations = Vec::new();
+    let mut debug_responses = Vec::new();
+    let mut tok = PassToken { schala: self, stage_durations: &mut stage_durations, sw: &sw, debug_requests: &debug_requests, debug_responses: &mut debug_responses };
+
+    let main_output: Result<String, String> = Ok(source)
+      .and_then(|source| output_wrapper(0, tokenizing, source, &mut tok))
+      .and_then(|tokens| output_wrapper(1, parsing, tokens, &mut tok))
+      .and_then(|ast| output_wrapper(2, symbol_table, ast, &mut tok))
+      .and_then(|ast| output_wrapper(3, typechecking, ast, &mut tok))
+      .and_then(|ast| output_wrapper(4, ast_reducing, ast, &mut tok))
+      .and_then(|reduced_ast| output_wrapper(5, eval, reduced_ast, &mut tok));
+
+    let total_duration = sw.elapsed();
+    let global_output_stats = GlobalOutputStats {
+      total_duration, stage_durations
+    };
+
+    ComputationResponse {
+      main_output,
+      global_output_stats,
+      debug_responses,
+    }
+  }
+
+  fn request_meta(&mut self, request: LangMetaRequest) -> LangMetaResponse {
+    match request {
+      LangMetaRequest::StageNames => LangMetaResponse::StageNames(stage_names().iter().map(|s| s.to_string()).collect()),
+      LangMetaRequest::Docs { source } => self.handle_docs(source),
+      LangMetaRequest::ImmediateDebug(debug_request) =>
+        LangMetaResponse::ImmediateDebug(self.handle_debug_immediate(debug_request)),
+      LangMetaRequest::Custom { .. } => LangMetaResponse::Custom { kind: format!("not-implemented"), value: format!("") }
+    }
+  }
+}

schala-lang/language/src/prelude.schala

@@ -0,0 +1,13 @@
+
+type Option<T> = Some(T) | None
+type Color = Red | Green | Blue
+type Ord = LT | EQ | GT
+
+
+fn map(input: Option<T>, func: Func): Option<T> {
+  if input {
+    is Some(x) -> Some(func(x)),
+    is None -> None,
+  }
+}
+  

schala-lang/language/src/reduced_ast.rs

@@ -0,0 +1,397 @@
+use std::rc::Rc;
+
+use crate::ast::*;
+use crate::symbol_table::{Symbol, SymbolSpec, SymbolTable};
+use crate::builtin::{BinOp, PrefixOp};
+
+#[derive(Debug)]
+pub struct ReducedAST(pub Vec<Stmt>);
+
+#[derive(Debug, Clone)]
+pub enum Stmt {
+  PreBinding {
+    name: Rc<String>,
+    func: Func,
+  },
+  Binding {
+    name: Rc<String>,
+    constant: bool,
+    expr: Expr,
+  },
+  Expr(Expr),
+  Noop,
+}
+
+#[derive(Debug, Clone)]
+pub enum Expr {
+  Unit,
+  Lit(Lit),
+  Tuple(Vec<Expr>),
+  Func(Func),
+  Val(Rc<String>),
+  Constructor {
+    type_name: Rc<String>,
+    name: Rc<String>,
+    tag: usize,
+    arity: usize,
+  },
+  Call {
+    f: Box<Expr>,
+    args: Vec<Expr>,
+  },
+  Assign {
+    val: Box<Expr>,
+    expr: Box<Expr>,
+  },
+  Conditional {
+    cond: Box<Expr>,
+    then_clause: Vec<Stmt>,
+    else_clause: Vec<Stmt>,
+  },
+  ConditionalTargetSigilValue,
+  CaseMatch {
+    cond: Box<Expr>,
+    alternatives: Vec<Alternative>
+  },
+  UnimplementedSigilValue
+}
+
+pub type BoundVars = Vec<Option<Rc<String>>>; //remember that order matters here
+
+#[derive(Debug, Clone)]
+pub struct Alternative {
+  pub tag: Option<usize>,
+  pub subpatterns: Vec<Option<Subpattern>>,
+  pub guard: Option<Expr>,
+  pub bound_vars: BoundVars,
+  pub item: Vec<Stmt>,
+}
+
+#[derive(Debug, Clone)]
+pub struct Subpattern {
+  pub tag: Option<usize>,
+  pub subpatterns: Vec<Option<Subpattern>>,
+  pub bound_vars: BoundVars,
+  pub guard: Option<Expr>,
+}
+
+#[derive(Debug, Clone)]
+pub enum Lit {
+  Nat(u64),
+  Int(i64),
+  Float(f64),
+  Bool(bool),
+  StringLit(Rc<String>),
+}
+
+#[derive(Debug, Clone)]
+pub enum Func {
+  BuiltIn(Rc<String>),
+  UserDefined {
+    name: Option<Rc<String>>,
+    params: Vec<Rc<String>>,
+    body: Vec<Stmt>,
+  }
+}
+
+impl AST {
+  pub fn reduce(&self, symbol_table: &SymbolTable) -> ReducedAST {
+    let mut output = vec![];
+    for statement in self.0.iter() {
+      output.push(statement.node().reduce(symbol_table));
+    }
+    ReducedAST(output)
+  }
+}
+
+impl Statement {
+  fn reduce(&self, symbol_table: &SymbolTable) -> Stmt { 
+    use crate::ast::Statement::*;
+    match self {
+      ExpressionStatement(expr) => Stmt::Expr(expr.node().reduce(symbol_table)),
+      Declaration(decl) => decl.reduce(symbol_table),
+    }
+  }
+}
+
+fn reduce_block(block: &Block, symbol_table: &SymbolTable) -> Vec<Stmt> {
+  block.iter().map(|stmt| stmt.node().reduce(symbol_table)).collect()
+}
+
+impl Expression {
+  fn reduce(&self, symbol_table: &SymbolTable) -> Expr {
+    use crate::ast::ExpressionKind::*;
+    let ref input = self.0;
+    match input {
+      NatLiteral(n) => Expr::Lit(Lit::Nat(*n)),
+      FloatLiteral(f) => Expr::Lit(Lit::Float(*f)),
+      StringLiteral(s) => Expr::Lit(Lit::StringLit(s.clone())),
+      BoolLiteral(b) => Expr::Lit(Lit::Bool(*b)),
+      BinExp(binop, lhs, rhs) => binop.reduce(symbol_table, lhs, rhs),
+      PrefixExp(op, arg) => op.reduce(symbol_table, arg),
+      Value(name) => match symbol_table.lookup_by_name(name) {
+        Some(Symbol { spec: SymbolSpec::DataConstructor { index, type_args, type_name}, .. }) => Expr::Constructor {
+          type_name: type_name.clone(),
+          name: name.clone(),
+          tag: index.clone(),
+          arity: type_args.len(),
+        },
+        _ => Expr::Val(name.clone()),
+      },
+      Call { f, arguments } => Expr::Call {
+        f: Box::new(f.node().reduce(symbol_table)),
+        args: arguments.iter().map(|arg| arg.node().reduce(symbol_table)).collect(),
+      },
+      TupleLiteral(exprs) => Expr::Tuple(exprs.iter().map(|e| e.node().reduce(symbol_table)).collect()),
+      IfExpression { discriminator, body } => reduce_if_expression(discriminator, body, symbol_table),
+      Lambda { params, body, .. } => reduce_lambda(params, body, symbol_table),
+      NamedStruct { .. } => Expr::UnimplementedSigilValue,
+      Index { .. } => Expr::UnimplementedSigilValue,
+      WhileExpression { .. } => Expr::UnimplementedSigilValue,
+      ForExpression { .. } => Expr::UnimplementedSigilValue,
+      ListLiteral { .. } => Expr::UnimplementedSigilValue,
+    }
+  }
+}
+
+fn reduce_lambda(params: &Vec<FormalParam>, body: &Block, symbol_table: &SymbolTable) -> Expr {
+  Expr::Func(Func::UserDefined {
+    name: None,
+    params: params.iter().map(|param| param.0.clone()).collect(),
+    body: reduce_block(body, symbol_table),
+  })
+}
+
+fn reduce_if_expression(discriminator: &Discriminator, body: &IfExpressionBody, symbol_table: &SymbolTable) -> Expr {
+  let cond = Box::new(match *discriminator {
+    Discriminator::Simple(ref expr) => expr.reduce(symbol_table),
+    Discriminator::BinOp(ref _expr, ref _binop) => panic!("Can't yet handle binop discriminators")
+  });
+  match *body {
+    IfExpressionBody::SimpleConditional(ref then_clause, ref else_clause) => {
+      let then_clause = reduce_block(then_clause, symbol_table);
+      let else_clause = match else_clause {
+        None => vec![],
+        Some(stmts) => reduce_block(stmts, symbol_table),
+      };
+      Expr::Conditional { cond, then_clause, else_clause }
+    },
+    IfExpressionBody::SimplePatternMatch(ref pat, ref then_clause, ref else_clause) => {
+      let then_clause = reduce_block(then_clause, symbol_table);
+      let else_clause = match else_clause {
+        None => vec![],
+        Some(stmts) => reduce_block(stmts, symbol_table),
+      };
+
+      let alternatives = vec![
+        pat.to_alternative(then_clause, symbol_table),
+        Alternative {
+          tag: None,
+          subpatterns: vec![],
+          bound_vars: vec![],
+          guard: None,
+          item: else_clause
+        },
+      ];
+
+      Expr::CaseMatch {
+        cond,
+        alternatives,
+      }
+    },
+    IfExpressionBody::GuardList(ref guard_arms) => {
+      let mut alternatives = vec![];
+      for arm in guard_arms {
+        match arm.guard {
+          Guard::Pat(ref p) =>  {
+            let item = reduce_block(&arm.body, symbol_table);
+            let alt = p.to_alternative(item, symbol_table);
+            alternatives.push(alt);
+          },
+          Guard::HalfExpr(HalfExpr { op: _, expr: _ }) => {
+            return Expr::UnimplementedSigilValue
+          }
+        }
+      }
+      Expr::CaseMatch { cond, alternatives }
+    }
+  }
+}
+/*                     ig var   pat
+ * x is SomeBigOldEnum(_, x, Some(t))
+ */
+
+fn handle_symbol(symbol: Option<&Symbol>, inner_patterns: &Vec<Pattern>, symbol_table: &SymbolTable) -> Subpattern {
+  use self::Pattern::*;
+  let tag = symbol.map(|symbol| match symbol.spec {
+    SymbolSpec::DataConstructor { index, .. } => index.clone(),
+    _ => panic!("Symbol is not a data constructor - this should've been caught in type-checking"),
+  });
+  let bound_vars = inner_patterns.iter().map(|p| match p {
+    Literal(PatternLiteral::VarPattern(var)) => Some(var.clone()),
+    _ => None,
+  }).collect();
+
+  let subpatterns = inner_patterns.iter().map(|p| match p {
+    Ignored => None,
+    Literal(PatternLiteral::VarPattern(_)) => None,
+    Literal(other) => Some(other.to_subpattern(symbol_table)),
+    tp @ TuplePattern(_) => Some(tp.to_subpattern(symbol_table)),
+    ts @ TupleStruct(_, _) => Some(ts.to_subpattern(symbol_table)),
+    Record(..) => unimplemented!(),
+  }).collect();
+
+  let guard = None;
+  /*
+     let guard_equality_exprs: Vec<Expr> = subpatterns.iter().map(|p| match p {
+     Literal(lit) => match lit {
+     _ => unimplemented!()
+     },
+     _ => unimplemented!()
+     }).collect();
+     */
+
+  Subpattern {
+    tag,
+    subpatterns,
+    guard,
+    bound_vars,
+  }
+}
+
+impl Pattern {
+  fn to_alternative(&self, item: Vec<Stmt>, symbol_table: &SymbolTable) -> Alternative {
+    let s = self.to_subpattern(symbol_table);
+    Alternative {
+      tag: s.tag,
+      subpatterns: s.subpatterns,
+      bound_vars: s.bound_vars,
+      guard: s.guard,
+      item
+    }
+  }
+
+  fn to_subpattern(&self, symbol_table: &SymbolTable) -> Subpattern {
+    use self::Pattern::*;
+    match self {
+      TupleStruct(name, inner_patterns) => {
+        let symbol = symbol_table.lookup_by_name(name).expect(&format!("Symbol {} not found", name));
+        handle_symbol(Some(symbol), inner_patterns, symbol_table)
+      },
+      TuplePattern(inner_patterns) => handle_symbol(None, inner_patterns, symbol_table),
+      Record(_name, _pairs) => {
+        unimplemented!()
+      },
+      Ignored => Subpattern { tag: None, subpatterns: vec![], guard: None, bound_vars: vec![] },
+      Literal(lit) => lit.to_subpattern(symbol_table),
+    }
+  }
+}
+
+impl PatternLiteral {
+  fn to_subpattern(&self, symbol_table: &SymbolTable) -> Subpattern {
+    use self::PatternLiteral::*;
+    match self {
+      NumPattern { neg, num } => {
+        let comparison = Expr::Lit(match (neg, num) {
+          (false, ExpressionKind::NatLiteral(n)) => Lit::Nat(*n),
+          (false, ExpressionKind::FloatLiteral(f)) => Lit::Float(*f),
+          (true, ExpressionKind::NatLiteral(n)) => Lit::Int(-1*(*n as i64)),
+          (true, ExpressionKind::FloatLiteral(f)) => Lit::Float(-1.0*f),
+          _ => panic!("This should never happen")
+        });
+        let guard = Some(Expr::Call {
+          f: Box::new(Expr::Func(Func::BuiltIn(Rc::new("==".to_string())))),
+          args: vec![comparison, Expr::ConditionalTargetSigilValue],
+        });
+        Subpattern {
+          tag: None,
+          subpatterns: vec![],
+          guard,
+          bound_vars: vec![],
+        }
+      },
+      StringPattern(s) => {
+        let guard = Some(Expr::Call {
+          f: Box::new(Expr::Func(Func::BuiltIn(Rc::new("==".to_string())))),
+          args: vec![Expr::Lit(Lit::StringLit(s.clone())), Expr::ConditionalTargetSigilValue]
+        });
+
+        Subpattern {
+          tag: None,
+          subpatterns: vec![],
+          guard,
+          bound_vars: vec![],
+        }
+      },
+      BoolPattern(b) =>  {
+        let guard = Some(if *b {
+          Expr::ConditionalTargetSigilValue
+        } else {
+          Expr::Call {
+            f: Box::new(Expr::Func(Func::BuiltIn(Rc::new("!".to_string())))),
+            args: vec![Expr::ConditionalTargetSigilValue]
+          }
+        });
+        Subpattern {
+          tag: None,
+          subpatterns: vec![],
+          guard,
+          bound_vars: vec![],
+        }
+      },
+      VarPattern(var) => match symbol_table.lookup_by_name(var) {
+        Some(symbol) => handle_symbol(Some(symbol), &vec![], symbol_table),
+        None => Subpattern {
+          tag: None,
+          subpatterns: vec![],
+          guard: None,
+          bound_vars: vec![Some(var.clone())],
+        }
+      }
+    }
+  }
+}
+
+impl Declaration {
+  fn reduce(&self, symbol_table: &SymbolTable) -> Stmt {
+    use self::Declaration::*;
+    match self {
+      Binding {name, constant, expr, .. } => Stmt::Binding { name: name.clone(), constant: *constant, expr: expr.node().reduce(symbol_table) },
+      FuncDecl(Signature { name, params, .. }, statements) => Stmt::PreBinding {
+        name: name.clone(),
+        func: Func::UserDefined {
+          name: Some(name.clone()),
+          params: params.iter().map(|param| param.0.clone()).collect(),
+          body: reduce_block(&statements, symbol_table),
+        }
+      },
+      TypeDecl { .. } => Stmt::Noop,
+      TypeAlias(_, _) => Stmt::Noop,
+      Interface { .. } => Stmt::Noop,
+      Impl { .. } => Stmt::Expr(Expr::UnimplementedSigilValue),
+      _ => Stmt::Expr(Expr::UnimplementedSigilValue)
+    }
+  }
+}
+
+impl BinOp {
+  fn reduce(&self, symbol_table: &SymbolTable, lhs: &Box<Meta<Expression>>, rhs: &Box<Meta<Expression>>) -> Expr {
+    if **self.sigil() == "=" {
+      Expr::Assign {
+        val: Box::new(lhs.node().reduce(symbol_table)),
+        expr: Box::new(rhs.node().reduce(symbol_table)),
+      }
+    } else {
+      let f = Box::new(Expr::Func(Func::BuiltIn(self.sigil().clone())));
+      Expr::Call { f, args: vec![lhs.node().reduce(symbol_table), rhs.node().reduce(symbol_table)]}
+    }
+  }
+}
+
+impl PrefixOp {
+  fn reduce(&self, symbol_table: &SymbolTable, arg: &Box<Meta<Expression>>) -> Expr {
+    let f = Box::new(Expr::Func(Func::BuiltIn(self.sigil().clone())));
+    Expr::Call { f, args: vec![arg.node().reduce(symbol_table)]}
+  }
+}

schala-lang/language/src/symbol_table.rs

@@ -0,0 +1,391 @@
+use std::collections::HashMap;
+use std::collections::hash_map::Entry;
+use std::rc::Rc;
+use std::fmt;
+use std::fmt::Write;
+
+use crate::ast;
+use crate::ast::{Meta, TypeBody, TypeSingletonName, Signature, Statement};
+use crate::typechecking::TypeName;
+
+type LineNumber = u32;
+type SymbolTrackTable = HashMap<Rc<String>, LineNumber>;
+
+#[derive(PartialEq, Eq, Hash, Debug)]
+struct PathToSymbol(Vec<Rc<String>>);
+
+#[derive(Debug, Clone)]
+struct ScopeSegment {
+  scope_name: Rc<String>,
+  scope_type: ScopeSegmentKind,
+}
+
+#[derive(Debug, Clone)]
+enum ScopeSegmentKind {
+  Function,
+  //Type,
+}
+
+//cf. p. 150 or so of Language Implementation Patterns
+pub struct SymbolTable {
+  values: HashMap<PathToSymbol, Symbol>,
+}
+
+//TODO add various types of lookups here, maybe multiple hash tables internally?
+impl SymbolTable {
+  pub fn new() -> SymbolTable {
+    SymbolTable {
+      values: HashMap::new(),
+    }
+  }
+
+  fn add_new_symbol(&mut self, name: &Rc<String>, scope_path: &Vec<ScopeSegment>, spec: SymbolSpec) {
+    let mut vec: Vec<Rc<String>> = scope_path.iter().map(|segment| segment.scope_name.clone()).collect();
+    vec.push(name.clone());
+    let symbol_path = PathToSymbol(vec);
+    let symbol = Symbol { name: name.clone(), scopes: scope_path.to_vec(), spec };
+    self.values.insert(symbol_path, symbol);
+  }
+
+  pub fn lookup_by_name(&self, name: &Rc<String>) -> Option<&Symbol> {
+    self.lookup_by_path(name, &vec![])
+  }
+
+  pub fn lookup_by_path(&self, name: &Rc<String>, path: &Vec<Rc<String>>) -> Option<&Symbol> {
+    let mut vec = path.clone();
+    vec.push(name.clone());
+    let symbol_path = PathToSymbol(vec);
+    self.values.get(&symbol_path)
+  }
+}
+
+#[derive(Debug)]
+pub struct Symbol {
+  pub name: Rc<String>, //TODO does this need to be pub?
+  scopes: Vec<ScopeSegment>,
+  pub spec: SymbolSpec,
+}
+
+impl fmt::Display for Symbol {
+  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    write!(f, "<Name: {}, Spec: {}>", self.name, self.spec)
+  }
+}
+
+#[derive(Debug)]
+pub enum SymbolSpec {
+  Func(Vec<TypeName>),
+  DataConstructor {
+    index: usize,
+    type_name: Rc<String>,
+    type_args: Vec<Rc<String>>,
+  },
+  RecordConstructor {
+    fields: HashMap<Rc<String>, Rc<String>>
+  },
+  Binding
+}
+
+impl fmt::Display for SymbolSpec {
+  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    use self::SymbolSpec::*;
+    match self {
+      Func(type_names) => write!(f, "Func({:?})", type_names),
+      DataConstructor { index, type_name, type_args } => write!(f, "DataConstructor(idx: {})({:?} -> {})", index, type_args, type_name),
+      RecordConstructor { fields: _fields } => write!(f, "RecordConstructor( <fields> )"),
+      Binding => write!(f, "Binding"),
+    }
+  }
+}
+
+impl SymbolTable {
+  /* note: this adds names for *forward reference* but doesn't actually create any types. solve that problem
+   * later */
+
+  pub fn add_top_level_symbols(&mut self, ast: &ast::AST) -> Result<(), String> {
+    let mut scope_name_stack = Vec::new();
+    self.add_symbols_from_scope(&ast.0, &mut scope_name_stack)
+  }
+
+  fn add_symbols_from_scope<'a>(&'a mut self, statements: &Vec<Meta<Statement>>, scope_name_stack: &mut Vec<ScopeSegment>) -> Result<(), String> {
+    use self::ast::Declaration::*;
+
+    fn insert_and_check_duplicate_symbol(table: &mut SymbolTrackTable, name: &Rc<String>) -> Result<(), String> {
+      match table.entry(name.clone()) {
+        Entry::Occupied(o) => {
+          let line_number = o.get(); //TODO make this actually work
+          Err(format!("Duplicate definition: {}. It's already defined at {}", name, line_number))
+        },
+        Entry::Vacant(v) => {
+          let line_number = 0; //TODO should work
+          v.insert(line_number);
+          Ok(())
+        }
+      }
+    }
+
+    let mut seen_identifiers: SymbolTrackTable = HashMap::new();
+
+    for meta in statements.iter() {
+      let statement = meta.node();
+      if let Statement::Declaration(decl) = statement {
+        match decl {
+          FuncSig(ref signature) => {
+            insert_and_check_duplicate_symbol(&mut seen_identifiers, &signature.name)?;
+            self.add_function_signature(signature, scope_name_stack)?
+          }
+          FuncDecl(ref signature, ref body) => {
+            insert_and_check_duplicate_symbol(&mut seen_identifiers, &signature.name)?;
+            self.add_function_signature(signature, scope_name_stack)?;
+            scope_name_stack.push(ScopeSegment{
+              scope_name: signature.name.clone(),
+              scope_type: ScopeSegmentKind::Function,
+            });
+            let output = self.add_symbols_from_scope(body, scope_name_stack);
+            let _ = scope_name_stack.pop();
+            output?
+          },
+          TypeDecl { name, body, mutable } => {
+            insert_and_check_duplicate_symbol(&mut seen_identifiers, &name.name)?;
+            self.add_type_decl(name, body, mutable, scope_name_stack)?
+          },
+          Binding { name, .. } => {
+            insert_and_check_duplicate_symbol(&mut seen_identifiers, name)?;
+            self.add_new_symbol(name, scope_name_stack, SymbolSpec::Binding);
+          }
+          _ => ()
+        }
+      }
+    }
+    Ok(())
+  }
+  pub fn debug_symbol_table(&self) -> String {
+    let mut output = format!("Symbol table\n");
+    for (name, sym) in &self.values {
+      write!(output, "{:?} -> {}\n", name, sym).unwrap();
+    }
+    output
+  }
+
+  fn add_function_signature(&mut self, signature: &Signature, scope_name_stack: &mut Vec<ScopeSegment>) -> Result<(), String> {
+    let mut local_type_context = LocalTypeContext::new();
+    let types = signature.params.iter().map(|param| match param {
+      (_, Some(type_identifier)) => Rc::new(format!("{:?}", type_identifier)),
+      (_, None) => local_type_context.new_universal_type()
+    }).collect();
+    self.add_new_symbol(&signature.name, scope_name_stack, SymbolSpec::Func(types));
+    Ok(())
+  }
+
+  fn add_type_decl(&mut self, type_name: &TypeSingletonName, body: &TypeBody, _mutable: &bool, scope_name_stack: &mut Vec<ScopeSegment>) -> Result<(), String> {
+    use crate::ast::{TypeIdentifier, Variant};
+    let TypeBody(variants) = body;
+    let TypeSingletonName { name, .. } = type_name;
+    //scope_name_stack.push(name.clone()); //TODO adding this makes variants scoped under their
+    //type name and breaks a lot of things - don't add it until importing names works
+    //TODO figure out why _params isn't being used here
+    for (index, var) in variants.iter().enumerate() {
+      match var {
+        Variant::UnitStruct(variant_name) => {
+          let spec = SymbolSpec::DataConstructor {
+            index,
+            type_name: name.clone(),
+            type_args: vec![],
+          };
+          self.add_new_symbol(variant_name, scope_name_stack, spec);
+        },
+        Variant::TupleStruct(variant_name, tuple_members) => {
+          let type_args = tuple_members.iter().map(|type_name| match type_name {
+            TypeIdentifier::Singleton(TypeSingletonName { name, ..}) => name.clone(),
+            TypeIdentifier::Tuple(_) => unimplemented!(),
+          }).collect();
+          let spec = SymbolSpec::DataConstructor {
+            index,
+            type_name: name.clone(),
+            type_args
+          };
+          self.add_new_symbol(variant_name, scope_name_stack, spec);
+        },
+        //TODO if there is only one variant, and it is a record, it doesn't need to have an
+        //explicit name
+        Variant::Record { name, members: _members } => {
+          let fields = HashMap::new();
+          let spec = SymbolSpec::RecordConstructor { fields };
+          self.add_new_symbol(name, scope_name_stack, spec);
+        },
+      }
+    }
+    //scope_name_stack.pop();
+    Ok(())
+  }
+}
+
+struct LocalTypeContext {
+  state: u8
+}
+impl LocalTypeContext {
+  fn new() -> LocalTypeContext {
+    LocalTypeContext { state: 0 }
+  }
+
+  fn new_universal_type(&mut self) -> TypeName {
+    let n = self.state;
+    self.state += 1;
+    Rc::new(format!("{}", (('a' as u8) + n) as char))
+  }
+}
+
+
+#[cfg(test)]
+mod symbol_table_tests {
+  use super::*;
+  use crate::util::quick_ast;
+
+  macro_rules! values_in_table {
+    //TODO multiple values
+    ($source:expr, $single_value:expr) => {
+      {
+      let mut symbol_table = SymbolTable::new();
+      let ast = quick_ast($source);
+      symbol_table.add_top_level_symbols(&ast).unwrap();
+      match symbol_table.lookup_by_name($single_value) {
+        Some(_spec) => (),
+        None => panic!(),
+      };
+      }
+    }
+  }
+
+  #[test]
+  fn basic_symbol_table() {
+    values_in_table! { "let a = 10; fn b() { 20 }", &rc!(b) };
+  }
+
+  #[test]
+  fn no_duplicates() {
+    let source = r#"
+    fn a() { 1 }
+    fn b() { 2 }
+    fn a() { 3 }
+    "#;
+    let mut symbol_table = SymbolTable::new();
+    let ast = quick_ast(source);
+    let output = symbol_table.add_top_level_symbols(&ast).unwrap_err();
+    assert!(output.contains("Duplicate"))
+  }
+
+  #[test]
+  fn no_duplicates_2() {
+    let source = r#"
+    let a = 20;
+    let q = 39;
+    let a = 30;
+    "#;
+    let mut symbol_table = SymbolTable::new();
+    let ast = quick_ast(source);
+    let output = symbol_table.add_top_level_symbols(&ast).unwrap_err();
+    assert!(output.contains("Duplicate"))
+  }
+
+  #[test]
+  fn no_duplicates_3() {
+    let source = r#"
+    fn a() {
+      let a = 20
+      let b = 40
+      a + b
+    }
+
+    fn q() {
+      let x = 30
+      let x = 33
+    }
+    "#;
+    let mut symbol_table = SymbolTable::new();
+    let ast = quick_ast(source);
+    let output = symbol_table.add_top_level_symbols(&ast).unwrap_err();
+    assert!(output.contains("Duplicate"))
+  }
+
+  #[test]
+  fn dont_falsely_detect_duplicates() {
+    let source = r#"
+    let a = 20;
+    fn some_func() {
+      let a = 40;
+      77
+    }
+    let q = 39;
+    "#;
+    let mut symbol_table = SymbolTable::new();
+    let ast = quick_ast(source);
+    symbol_table.add_top_level_symbols(&ast).unwrap();
+    assert!(symbol_table.lookup_by_path(&rc!(a), &vec![]).is_some());
+    assert!(symbol_table.lookup_by_path(&rc!(a), &vec![rc!(some_func)]).is_some());
+  }
+
+  #[test]
+  fn enclosing_scopes() {
+    let source = r#"
+fn outer_func(x) {
+  fn inner_func(arg) {
+    arg
+  }
+  x + inner_func(x)
+}"#;
+    let mut symbol_table = SymbolTable::new();
+    let ast = quick_ast(source);
+    symbol_table.add_top_level_symbols(&ast).unwrap();
+    assert!(symbol_table.lookup_by_path(&rc!(outer_func), &vec![]).is_some());
+    assert!(symbol_table.lookup_by_path(&rc!(inner_func), &vec![rc!(outer_func)]).is_some());
+  }
+
+  #[test]
+  fn enclosing_scopes_2() {
+    let source = r#"
+fn outer_func(x) {
+  fn inner_func(arg) {
+    arg
+  }
+
+  fn second_inner_func() {
+    fn another_inner_func() {
+    }
+  }
+
+  inner_func(x)
+}"#;
+    let mut symbol_table = SymbolTable::new();
+    let ast = quick_ast(source);
+    symbol_table.add_top_level_symbols(&ast).unwrap();
+    println!("{}", symbol_table.debug_symbol_table());
+    assert!(symbol_table.lookup_by_path(&rc!(outer_func), &vec![]).is_some());
+    assert!(symbol_table.lookup_by_path(&rc!(inner_func), &vec![rc!(outer_func)]).is_some());
+    assert!(symbol_table.lookup_by_path(&rc!(second_inner_func), &vec![rc!(outer_func)]).is_some());
+    assert!(symbol_table.lookup_by_path(&rc!(another_inner_func), &vec![rc!(outer_func), rc!(second_inner_func)]).is_some());
+  }
+
+  #[test]
+  fn enclosing_scopes_3() {
+    let source = r#"
+fn outer_func(x) {
+  fn inner_func(arg) {
+    arg
+  }
+
+  fn second_inner_func() {
+    fn another_inner_func() {
+    }
+    fn another_inner_func() {
+    }
+  }
+
+  inner_func(x)
+}"#;
+    let mut symbol_table = SymbolTable::new();
+    let ast = quick_ast(source);
+    let output = symbol_table.add_top_level_symbols(&ast).unwrap_err();
+    assert!(output.contains("Duplicate"))
+  }
+}
+

schala-lang/language/src/tokenizing.rs

@@ -0,0 +1,324 @@
+use itertools::Itertools;
+use std::collections::HashMap;
+use std::rc::Rc;
+use std::iter::{Iterator, Peekable};
+use std::fmt;
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum TokenKind {
+  Newline, Semicolon,
+
+  LParen, RParen,
+  LSquareBracket, RSquareBracket,
+  LAngleBracket, RAngleBracket,
+  LCurlyBrace, RCurlyBrace,
+  Pipe, Backslash,
+
+  Comma, Period, Colon, Underscore,
+  Slash,
+
+  Operator(Rc<String>),
+  DigitGroup(Rc<String>), HexLiteral(Rc<String>), BinNumberSigil,
+  StrLiteral(Rc<String>),
+  Identifier(Rc<String>),
+  Keyword(Kw),
+
+  EOF,
+
+  Error(String),
+}
+use self::TokenKind::*;
+
+impl fmt::Display for TokenKind {
+  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    match self {
+      &Operator(ref s) => write!(f, "Operator({})", **s),
+      &DigitGroup(ref s) => write!(f, "DigitGroup({})", s),
+      &HexLiteral(ref s) => write!(f, "HexLiteral({})", s),
+      &StrLiteral(ref s) => write!(f, "StrLiteral({})", s),
+      &Identifier(ref s) => write!(f, "Identifier({})", s),
+      &Error(ref s) => write!(f, "Error({})", s),
+      other => write!(f, "{:?}", other),
+    }
+  }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum Kw {
+  If, Then, Else,
+  Is,
+  Func,
+  For, While,
+  Const, Let, In,
+  Mut,
+  Return,
+  Alias, Type, SelfType, SelfIdent,
+  Interface, Impl,
+  True, False,
+  Module
+}
+
+lazy_static! {
+  static ref KEYWORDS: HashMap<&'static str, Kw> =
+    hashmap! {
+      "if" => Kw::If,
+      "then" => Kw::Then,
+      "else" => Kw::Else,
+      "is" => Kw::Is,
+      "fn" => Kw::Func,
+      "for" => Kw::For,
+      "while" => Kw::While,
+      "const" => Kw::Const,
+      "let" => Kw::Let,
+      "in" => Kw::In,
+      "mut" => Kw::Mut,
+      "return" => Kw::Return,
+      "alias" => Kw::Alias,
+      "type" => Kw::Type,
+      "Self" => Kw::SelfType,
+      "self" => Kw::SelfIdent,
+      "interface" => Kw::Interface,
+      "impl" => Kw::Impl,
+      "true" => Kw::True,
+      "false" => Kw::False,
+      "module" => Kw::Module,
+    };
+}
+
+#[derive(Debug, Clone)]
+pub struct Token {
+  pub kind: TokenKind,
+  pub line_num: usize,
+  pub char_num: usize
+}
+
+impl Token {
+  pub fn get_error(&self) -> Option<String> {
+    match self.kind {
+      TokenKind::Error(ref s) => Some(s.clone()),
+      _ => None,
+    }
+  }
+  pub fn to_string_with_metadata(&self) -> String {
+    format!("{}(L:{},c:{})", self.kind, self.line_num, self.char_num)
+  }
+
+  pub fn get_kind(&self) -> TokenKind {
+    self.kind.clone()
+  }
+}
+
+const OPERATOR_CHARS: [char; 18] = ['!', '$', '%', '&', '*', '+', '-', '.', ':', '<', '>', '=', '?', '@', '^', '|', '~', '`'];
+fn is_operator(c: &char) -> bool {
+  OPERATOR_CHARS.iter().any(|x| x == c)
+}
+
+type CharData = (usize, usize, char);
+
+pub fn tokenize(input: &str) -> Vec<Token> {
+  let mut tokens: Vec<Token> = Vec::new();
+
+  let mut input  = input.lines().enumerate()
+      .intersperse((0, "\n"))
+      .flat_map(|(line_idx, ref line)| {
+          line.chars().enumerate().map(move |(ch_idx, ch)| (line_idx, ch_idx, ch))
+      })
+      .peekable();
+
+  while let Some((line_num, char_num, c)) = input.next() {
+    let cur_tok_kind = match c {
+      '/' => match input.peek().map(|t| t.2) {
+        Some('/') => {
+          while let Some((_, _, c)) = input.next() {
+            if c == '\n' {
+              break;
+            }
+          }
+          continue;
+        },
+        Some('*') => {
+          input.next();
+          let mut comment_level = 1;
+          while let Some((_, _, c)) = input.next() {
+            if c == '*'  && input.peek().map(|t| t.2) == Some('/') {
+              input.next();
+              comment_level -= 1;
+            } else if c == '/' && input.peek().map(|t| t.2) == Some('*') {
+              input.next();
+              comment_level += 1;
+            }
+            if comment_level == 0 {
+              break;
+            }
+          }
+          continue;
+        },
+        _ => Slash
+      },
+      c if c.is_whitespace() && c != '\n' => continue,
+      '\n' => Newline, ';' => Semicolon,
+      ':' => Colon, ',' => Comma,
+      '(' => LParen, ')' => RParen,
+      '{' => LCurlyBrace, '}' => RCurlyBrace,
+      '[' => LSquareBracket, ']' => RSquareBracket,
+      '"' => handle_quote(&mut input),
+      '\\' => Backslash,
+      c if c.is_digit(10) => handle_digit(c, &mut input),
+      c if c.is_alphabetic() || c == '_' => handle_alphabetic(c, &mut input),
+      c if is_operator(&c) => handle_operator(c, &mut input),
+      unknown => Error(format!("Unexpected character: {}", unknown)),
+    };
+    tokens.push(Token { kind: cur_tok_kind, line_num, char_num });
+  }
+  tokens
+}
+
+fn handle_digit(c: char, input: &mut Peekable<impl Iterator<Item=CharData>>) -> TokenKind {
+  if c == '0' && input.peek().map_or(false, |&(_, _, c)| { c == 'x' }) {
+    input.next();
+    let rest: String = input.peeking_take_while(|&(_, _, ref c)| c.is_digit(16) || *c == '_').map(|(_, _, c)| { c }).collect();
+    HexLiteral(Rc::new(rest))
+  } else if c == '0' && input.peek().map_or(false, |&(_, _, c)| { c == 'b' }) {
+    input.next();
+    BinNumberSigil
+  } else {
+    let mut buf = c.to_string();
+    buf.extend(input.peeking_take_while(|&(_, _, ref c)| c.is_digit(10)).map(|(_, _, c)| { c }));
+    DigitGroup(Rc::new(buf))
+  }
+}
+
+fn handle_quote(input: &mut Peekable<impl Iterator<Item=CharData>>) -> TokenKind {
+  let mut buf = String::new();
+  loop {
+    match input.next().map(|(_, _, c)| { c }) {
+      Some('"') => break,
+      Some('\\') => {
+        let next = input.peek().map(|&(_, _, c)| { c });
+        if next == Some('n') {
+          input.next();
+          buf.push('\n')
+        } else if next == Some('"') {
+          input.next();
+          buf.push('"');
+        } else if next == Some('t') {
+          input.next();
+          buf.push('\t');
+        }
+      },
+      Some(c) => buf.push(c),
+      None => return TokenKind::Error(format!("Unclosed string")),
+    }
+  }
+  TokenKind::StrLiteral(Rc::new(buf))
+}
+
+fn handle_alphabetic(c: char, input: &mut Peekable<impl Iterator<Item=CharData>>) -> TokenKind {
+  let mut buf = String::new();
+  buf.push(c);
+  if c == '_' && input.peek().map(|&(_, _, c)| { !c.is_alphabetic() }).unwrap_or(true) {
+    return TokenKind::Underscore
+  }
+
+  loop {
+    match input.peek().map(|&(_, _, c)| { c }) {
+      Some(c) if c.is_alphanumeric() || c == '_' => {
+        input.next();
+        buf.push(c);
+      },
+      _ => break,
+    }
+  }
+
+  match KEYWORDS.get(buf.as_str()) {
+    Some(kw) => TokenKind::Keyword(*kw),
+    None => TokenKind::Identifier(Rc::new(buf)),
+  }
+}
+
+fn handle_operator(c: char, input: &mut Peekable<impl Iterator<Item=CharData>>) -> TokenKind {
+  match c {
+    '<' | '>' | '|' | '.' => {
+      let ref next = input.peek().map(|&(_, _, c)| { c });
+      if !next.map(|n| { is_operator(&n) }).unwrap_or(false) {
+        return match c {
+          '<' => LAngleBracket,
+          '>' => RAngleBracket,
+          '|' => Pipe,
+          '.' => Period,
+          _ => unreachable!(),
+        }
+      }
+    },
+    _ => (),
+  };
+
+  let mut buf = String::new();
+
+  if c == '`' {
+    loop {
+      match input.peek().map(|&(_, _, c)| { c }) {
+        Some(c) if c.is_alphabetic() || c == '_' => {
+          input.next();
+          buf.push(c);
+        },
+        Some('`') => {
+          input.next();
+          break;
+        },
+        _ => break
+      }
+    }
+  } else {
+    buf.push(c);
+    loop {
+      match input.peek().map(|&(_, _, c)| { c }) {
+        Some(c) if is_operator(&c) => {
+          input.next();
+          buf.push(c);
+        },
+        _ => break
+      }
+    }
+  }
+  TokenKind::Operator(Rc::new(buf))
+}
+
+#[cfg(test)]
+mod schala_tokenizer_tests {
+  use super::*;
+  use super::Kw::*;
+
+  macro_rules! digit { ($ident:expr) => { DigitGroup(Rc::new($ident.to_string())) } }
+  macro_rules! ident { ($ident:expr) => { Identifier(Rc::new($ident.to_string())) } }
+  macro_rules! op { ($ident:expr) => { Operator(Rc::new($ident.to_string())) } }
+
+  #[test]
+  fn tokens() {
+    let a = tokenize("let a: A<B> = c ++ d");
+    let token_kinds: Vec<TokenKind> = a.into_iter().map(move |t| t.kind).collect();
+    assert_eq!(token_kinds, vec![Keyword(Let), ident!("a"), Colon, ident!("A"),
+      LAngleBracket, ident!("B"), RAngleBracket, op!("="), ident!("c"), op!("++"), ident!("d")]);
+  }
+
+  #[test]
+  fn underscores() {
+    let token_kinds: Vec<TokenKind> = tokenize("4_8").into_iter().map(move |t| t.kind).collect();
+    assert_eq!(token_kinds, vec![digit!("4"), Underscore, digit!("8")]);
+
+    let token_kinds2: Vec<TokenKind> = tokenize("aba_yo").into_iter().map(move |t| t.kind).collect();
+    assert_eq!(token_kinds2, vec![ident!("aba_yo")]);
+  }
+
+  #[test]
+  fn comments() {
+    let token_kinds: Vec<TokenKind> = tokenize("1  + /* hella /* bro */ */ 2").into_iter().map(move |t| t.kind).collect();
+    assert_eq!(token_kinds, vec![digit!("1"), op!("+"), digit!("2")]);
+  }
+
+  #[test]
+  fn backtick_operators() {
+    let token_kinds: Vec<TokenKind> = tokenize("1 `plus` 2").into_iter().map(move |t| t.kind).collect();
+    assert_eq!(token_kinds, vec![digit!("1"), op!("plus"), digit!("2")]);
+  }
+}

schala-lang/language/src/typechecking.rs

@@ -1,13 +1,11 @@
 use std::rc::Rc;
-use std::convert::TryFrom;
-use std::fmt;
+use std::fmt::Write;
 
 use ena::unify::{UnifyKey, InPlaceUnificationTable, UnificationTable, EqUnifyValue};
 
-use crate::builtin::Builtin;
 use crate::ast::*;
 use crate::util::ScopeStack;
-use crate::util::deref_optional_box;
+use crate::builtin::{PrefixOp, BinOp};
 
 
 #[derive(Debug, Clone, PartialEq)]
@@ -16,37 +14,12 @@ pub struct TypeData {
 }
 
 impl TypeData {
-  #[allow(dead_code)]
   pub fn new() -> TypeData {
     TypeData { ty: None }
   }
 }
 
-//TODO need to hook this into the actual typechecking system somehow
-#[derive(Debug, Clone)]
-pub struct TypeId {
-    local_name: Rc<String>
-}
-
-impl TypeId {
-    //TODO this is definitely incomplete
-    pub fn lookup_name(name: &str) -> TypeId {
-        TypeId {
-            local_name: Rc::new(name.to_string())
-        }
-    }
-
-    pub fn local_name(&self) -> &str {
-        self.local_name.as_ref()
-    }
-}
-
-impl fmt::Display for TypeId {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-    write!(f, "TypeId:{}", self.local_name)
-  }
-}
-
+pub type TypeName = Rc<String>;
 
 pub struct TypeContext<'a> {
   variable_map: ScopeStack<'a, Rc<String>, Type>,
@@ -65,7 +38,6 @@ impl TypeError {
   }
 }
 
-#[allow(dead_code)] // avoids warning from Compound
 #[derive(Debug, Clone, PartialEq)]
 pub enum Type {
   Const(TypeConst),
@@ -103,21 +75,18 @@ pub enum TypeConst {
 }
 
 impl TypeConst {
-    /*
-  #[allow(dead_code)]
   pub fn to_string(&self) -> String {
     use self::TypeConst::*;
     match self {
-      Unit => "()".to_string(),
-      Nat => "Nat".to_string(),
-      Int => "Int".to_string(),
-      Float => "Float".to_string(),
-      StringT => "String".to_string(),
-      Bool => "Bool".to_string(),
-      Ordering => "Ordering".to_string(),
+      Unit => format!("()"),
+      Nat => format!("Nat"),
+      Int => format!("Int"),
+      Float => format!("Float"),
+      StringT => format!("String"),
+      Bool => format!("Bool"),
+      Ordering => format!("Ordering"),
     }
   }
-    */
 }
 
 impl EqUnifyValue for TypeConst { }
@@ -136,15 +105,13 @@ macro_rules! ty {
 
 //TODO find a better way to capture the to/from string logic
 impl Type {
-    /*
-  #[allow(dead_code)]
   pub fn to_string(&self) -> String {
     use self::Type::*;
     match self {
       Const(c) => c.to_string(),
       Var(v) => format!("t_{}", v.0),
       Arrow { params, box ref ret } => {
-        if params.is_empty() {
+        if params.len() == 0 {
           format!("-> {}", ret.to_string())
         } else {
           let mut buf = String::new();
@@ -155,10 +122,9 @@ impl Type {
           buf
         }
       },
-      Compound { .. } => "<some compound type>".to_string()
+      Compound { .. } => format!("<some compound type>")
     }
   }
-    */
 
   fn from_string(string: &str) -> Option<Type> {
     Some(match string {
@@ -284,7 +250,7 @@ impl<'a> TypeContext<'a> {
     use self::TypeIdentifier::*;
     Ok(match name {
       Singleton(TypeSingletonName { name,.. }) =>  {
-        match Type::from_string(name) {
+        match Type::from_string(&name) {
           Some(ty) => ty,
           None => return TypeError::new(format!("Unknown type name: {}", name))
         }
@@ -298,46 +264,39 @@ impl<'a> TypeContext<'a> {
   /// the AST to ReducedAST
   pub fn typecheck(&mut self, ast: &AST) -> Result<Type, TypeError> {
     let mut returned_type = Type::Const(TypeConst::Unit);
-    for statement in ast.statements.statements.iter() {
-      returned_type = self.statement(statement)?;
+    for statement in ast.0.iter() {
+      returned_type = self.statement(statement.node())?;
     }
     Ok(returned_type)
   }
 
   fn statement(&mut self, statement: &Statement) -> InferResult<Type> {
-    match &statement.kind {
-      StatementKind::Expression(e) => self.expr(e),
-      StatementKind::Declaration(decl) => self.decl(decl),
-      StatementKind::Import(_) => Ok(ty!(Unit)),
-      StatementKind::Module(_) => Ok(ty!(Unit)),
+    match statement {
+      Statement::ExpressionStatement(e) => self.expr(e.node()),
+      Statement::Declaration(decl) => self.decl(decl),
     }
   }
 
   fn decl(&mut self, decl: &Declaration) -> InferResult<Type> {
     use self::Declaration::*;
-    if let Binding { name, expr, .. } = decl {
-        let ty = self.expr(expr)?;
+    match decl {
+      Binding { name, expr, .. } => {
+        let ty = self.expr(expr.node())?;
         self.variable_map.insert(name.clone(), ty);
+      },
+      _ => (),
     }
     Ok(ty!(Unit))
   }
 
-  fn invoc(&mut self, invoc: &InvocationArgument) -> InferResult<Type> {
-    use InvocationArgument::*;
-    match invoc {
-      Positional(expr) => self.expr(expr),
-      _ => Ok(ty!(Nat)) //TODO this is wrong
-    }
-  }
-
   fn expr(&mut self, expr: &Expression) -> InferResult<Type> {
     match expr {
-      Expression { kind, type_anno: Some(anno), .. } => {
-        let t1 = self.expr_type(kind)?;
+      Expression(expr_type, Some(anno)) => {
+        let t1 = self.expr_type(expr_type)?;
         let t2 = self.get_type_from_name(anno)?;
         self.unify(t2, t1)
       },
-      Expression { kind, type_anno: None, .. } => self.expr_type(kind)
+      Expression(expr_type, None) => self.expr_type(expr_type)
     }
   }
 
@@ -348,21 +307,20 @@ impl<'a> TypeContext<'a> {
       BoolLiteral(_) => ty!(Bool),
       FloatLiteral(_) => ty!(Float),
       StringLiteral(_) => ty!(StringT),
-      PrefixExp(op, expr) => self.prefix(op, expr)?,
-      BinExp(op, lhs, rhs) => self.binexp(op, lhs, rhs)?,
-      IfExpression { discriminator, body } => self.if_expr(deref_optional_box(discriminator), &**body)?,
+      PrefixExp(op, expr) => self.prefix(op, expr.node())?,
+      BinExp(op, lhs, rhs) => self.binexp(op, lhs.node(), rhs.node())?,
+      IfExpression { discriminator, body } => self.if_expr(discriminator, body)?,
       Value(val) => self.handle_value(val)?,
-      Call { box ref f, arguments } => self.call(f, arguments)?,
+      Call { box ref f, arguments } => self.call(f.node(), arguments)?,
       Lambda { params, type_anno, body } => self.lambda(params, type_anno, body)?,
       _ => ty!(Unit),
     })
   }
 
   fn prefix(&mut self, op: &PrefixOp, expr: &Expression) -> InferResult<Type> {
-    let builtin: Option<Builtin> = TryFrom::try_from(op).ok();
-    let tf = match builtin.map(|b| b.get_type()) {
-      Some(ty) => ty,
-      None => return TypeError::new("no type found")
+    let tf = match op.get_type() {
+      Ok(ty) => ty,
+      Err(e) => return TypeError::new(e)
     };
 
     let tx = self.expr(expr)?;
@@ -370,10 +328,9 @@ impl<'a> TypeContext<'a> {
   }
 
   fn binexp(&mut self, op: &BinOp, lhs: &Expression, rhs: &Expression) -> InferResult<Type> {
-    let builtin: Option<Builtin> = TryFrom::try_from(op).ok();
-    let tf = match builtin.map(|b| b.get_type()) {
-      Some(ty) => ty,
-      None => return TypeError::new("no type found"),
+    let tf = match op.get_type() {
+      Ok(ty) => ty,
+      Err(e) => return TypeError::new(e),
     };
 
     let t_lhs = self.expr(lhs)?;
@@ -382,15 +339,14 @@ impl<'a> TypeContext<'a> {
     self.handle_apply(tf, vec![t_lhs, t_rhs])
   }
 
-  fn if_expr(&mut self, discriminator: Option<&Expression>, body: &IfExpressionBody) -> InferResult<Type> {
-    use self::IfExpressionBody::*;
+  fn if_expr(&mut self, discriminator: &Discriminator, body: &IfExpressionBody) -> InferResult<Type> {
+    use self::Discriminator::*; use self::IfExpressionBody::*;
     match (discriminator, body) {
-      (Some(expr), SimpleConditional{ then_case, else_case }) => self.handle_simple_if(expr, then_case, else_case),
-      _ => TypeError::new("Complex conditionals not supported".to_string())
+      (Simple(expr), SimpleConditional(then_clause, else_clause)) => self.handle_simple_if(expr, then_clause, else_clause),
+      _ => TypeError::new(format!("Complex conditionals not supported"))
     }
   }
 
-  #[allow(clippy::ptr_arg)]
   fn handle_simple_if(&mut self, expr: &Expression, then_clause: &Block, else_clause: &Option<Block>) -> InferResult<Type> {
     let t1 = self.expr(expr)?;
     let t2 = self.block(then_clause)?;
@@ -403,10 +359,9 @@ impl<'a> TypeContext<'a> {
     self.unify(t2, t3)
   }
 
-  #[allow(clippy::ptr_arg)]
   fn lambda(&mut self, params: &Vec<FormalParam>, type_anno: &Option<TypeIdentifier>, _body: &Block) -> InferResult<Type> {
     let argument_types: InferResult<Vec<Type>> = params.iter().map(|param: &FormalParam| {
-      if let FormalParam { anno: Some(type_identifier), ..  } = param {
+      if let (_, Some(type_identifier)) = param {
         self.get_type_from_name(type_identifier)
       } else {
         Ok(Type::Var(self.fresh_type_variable()))
@@ -421,9 +376,9 @@ impl<'a> TypeContext<'a> {
     Ok(ty!(argument_types, ret_type))
   }
 
-  fn call(&mut self, f: &Expression, args: &[ InvocationArgument ]) -> InferResult<Type> {
+  fn call(&mut self, f: &Expression, args: &Vec<Meta<Expression>>) -> InferResult<Type> {
     let tf = self.expr(f)?;
-    let arg_types: InferResult<Vec<Type>> = args.iter().map(|ex| self.invoc(ex)).collect();
+    let arg_types: InferResult<Vec<Type>> = args.iter().map(|ex| self.expr(ex.node())).collect();
     let arg_types = arg_types?;
     self.handle_apply(tf, arg_types)
   }
@@ -437,25 +392,23 @@ impl<'a> TypeContext<'a> {
         t_ret.clone()
       },
       Type::Arrow { .. } => return TypeError::new("Wrong length"),
-      _ => return TypeError::new("Not a function".to_string())
+      _ => return TypeError::new(format!("Not a function"))
     })
   }
 
-  #[allow(clippy::ptr_arg)]
   fn block(&mut self, block: &Block) -> InferResult<Type> {
     let mut output = ty!(Unit);
-    for statement in block.statements.iter() {
+    for s in block.iter() {
+      let statement = s.node();
       output = self.statement(statement)?;
     }
     Ok(output)
   }
 
-  fn handle_value(&mut self, val: &QualifiedName) -> InferResult<Type> {
-    let QualifiedName { components: vec, .. } = val;
-    let var = &vec[0];
-    match self.variable_map.lookup(var) {
+  fn handle_value(&mut self, val: &Rc<String>) -> InferResult<Type> {
+    match self.variable_map.lookup(val) {
       Some(ty) => Ok(ty.clone()),
-      None => TypeError::new(format!("Couldn't find variable: {}", &var)),
+      None => TypeError::new(format!("Couldn't find variable: {}", val))
     }
   }
 
@@ -466,26 +419,26 @@ impl<'a> TypeContext<'a> {
       (Const(ref c1), Const(ref c2)) if c1 == c2 => Ok(Const(c1.clone())), //choice of c1 is arbitrary I *think*
       (a @ Var(_), b @ Const(_)) => self.unify(b, a),
       (Const(ref c1), Var(ref v2)) => {
-        self.unification_table.unify_var_value(*v2, Some(c1.clone()))
+        self.unification_table.unify_var_value(v2.clone(), Some(c1.clone()))
           .or_else(|_| TypeError::new(format!("Couldn't unify {:?} and {:?}", Const(c1.clone()), Var(*v2))))?;
         Ok(Const(c1.clone()))
       },
       (Var(v1), Var(v2)) => {
         //TODO add occurs check
-        self.unification_table.unify_var_var(v1, v2)
+        self.unification_table.unify_var_var(v1.clone(), v2.clone())
           .or_else(|e| {
             println!("Unify error: {:?}", e);
             TypeError::new(format!("Two type variables {:?} and {:?} couldn't unify", v1, v2))
           })?;
-        Ok(Var(v1)) //arbitrary decision I think
+        Ok(Var(v1.clone())) //arbitrary decision I think
       },
       (a, b) => TypeError::new(format!("{:?} and {:?} do not unify", a, b)),
     }
   }
 
   fn fresh_type_variable(&mut self) -> TypeVar {
-    
-    self.unification_table.new_key(None)
+    let new_type_var = self.unification_table.new_key(None);
+    new_type_var
   }
 }
 
@@ -496,7 +449,7 @@ mod typechecking_tests {
   macro_rules! assert_type_in_fresh_context {
     ($string:expr, $type:expr) => {
       let mut tc = TypeContext::new();
-      let ast = &crate::util::quick_ast($string);
+      let ref ast = crate::util::quick_ast($string);
       let ty = tc.typecheck(ast).unwrap();
       assert_eq!(ty, $type)
     }
@@ -507,16 +460,13 @@ mod typechecking_tests {
     assert_type_in_fresh_context!("1", ty!(Nat));
     assert_type_in_fresh_context!(r#""drugs""#, ty!(StringT));
     assert_type_in_fresh_context!("true", ty!(Bool));
+    assert_type_in_fresh_context!("-1", ty!(Int));
   }
 
   #[test]
   fn operators() {
-    //TODO fix these with new operator regime
-    /*
-    assert_type_in_fresh_context!("-1", ty!(Int));
     assert_type_in_fresh_context!("1 + 2", ty!(Nat));
     assert_type_in_fresh_context!("-2", ty!(Int));
     assert_type_in_fresh_context!("!true", ty!(Bool));
-    */
   }
 }

schala-lang/language/src/util.rs

@@ -0,0 +1,55 @@
+use std::collections::HashMap;
+use std::hash::Hash;
+use std::cmp::Eq;
+
+#[derive(Default, Debug)]
+pub struct ScopeStack<'a, T: 'a, V: 'a>  where T: Hash + Eq {
+  parent: Option<&'a ScopeStack<'a, T, V>>,
+  values: HashMap<T, V>,
+  scope_name: Option<String>
+}
+
+impl<'a, T, V> ScopeStack<'a, T, V> where T: Hash + Eq {
+  pub fn new(name: Option<String>) -> ScopeStack<'a, T, V> where T: Hash + Eq {
+    ScopeStack {
+      parent: None,
+      values: HashMap::new(),
+      scope_name: name
+    }
+  }
+  pub fn insert(&mut self, key: T, value: V) where T: Hash + Eq {
+    self.values.insert(key, value);
+  }
+  pub fn lookup(&self, key: &T) -> Option<&V> where T: Hash + Eq {
+    match (self.values.get(key), self.parent) {
+      (None, None) => None,
+      (None, Some(parent)) => parent.lookup(key),
+      (Some(value), _) => Some(value),
+    }
+  }
+
+  pub fn new_scope(&'a self, name: Option<String>) -> ScopeStack<'a, T, V> where T: Hash + Eq {
+    ScopeStack {
+      parent: Some(self),
+      values: HashMap::default(),
+      scope_name: name,
+    }
+  }
+  #[allow(dead_code)]
+  pub fn get_name(&self) -> Option<&String> {
+    self.scope_name.as_ref()
+  }
+}
+
+/// this is intended for use in tests, and does no error-handling whatsoever
+#[allow(dead_code)]
+pub fn quick_ast(input: &str) -> crate::ast::AST {
+  let tokens = crate::tokenizing::tokenize(input);
+  let mut parser = crate::parsing::Parser::new(tokens);
+  parser.parse().unwrap()
+}
+
+#[allow(unused_macros)]
+macro_rules! rc {
+  ($string:tt) => { Rc::new(stringify!($string).to_string()) }
+}

schala-lang/source-files/prelude.schala

@@ -1,22 +0,0 @@
-let _SCHALA_VERSION = "0.1.0"
-
-type Option<T> = Some(T) | None
-type Ord = LT | EQ | GT
-
-@register_builtin(print)
-fn print(arg) { }
-
-@register_builtin(println)
-fn println(arg) { }
-
-@register_builtin(getline)
-fn getline(arg) { }
-
-fn map(input: Option<T>, func: Func): Option<T> {
-  if input {
-    is Option::Some(x) then Option::Some(func(x))
-    is Option::None then Option::None
-  }
-}
-
-type Complicated = Sunrise | Metal { black: bool, norwegian: bool } | Fella(String, Int)

schala-lang/src/ast/mod.rs

@@ -1,345 +0,0 @@
-#![allow(clippy::upper_case_acronyms)]
-#![allow(clippy::enum_variant_names)]
-
-use std::{
-    convert::{AsRef, From},
-    fmt,
-    rc::Rc,
-};
-
-mod operators;
-mod visitor;
-mod visualize;
-
-pub use operators::{BinOp, PrefixOp};
-pub use visitor::*;
-
-use crate::{
-    derivative::Derivative,
-    identifier::{define_id_kind, Id},
-    parsing::Location,
-    util::delim_wrapped,
-};
-
-define_id_kind!(ASTItem);
-
-pub type ItemId = Id<ASTItem>;
-
-#[derive(Derivative, Debug)]
-#[derivative(PartialEq)]
-pub struct AST {
-    #[derivative(PartialEq = "ignore")]
-    pub id: ItemId,
-    pub statements: Block,
-}
-
-impl fmt::Display for AST {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "{}", visualize::render_ast(self))
-    }
-}
-
-#[derive(Derivative, Debug, Clone)]
-#[derivative(PartialEq)]
-pub struct Statement<K> {
-    #[derivative(PartialEq = "ignore")]
-    pub id: ItemId,
-    #[derivative(PartialEq = "ignore")]
-    pub location: Location,
-    pub kind: K,
-}
-
-#[derive(Debug, PartialEq, Clone)]
-pub enum StatementKind {
-    Expression(Expression),
-    Declaration(Declaration),
-    Import(ImportSpecifier),
-    Flow(FlowControl),
-}
-
-#[derive(Debug, Clone, PartialEq)]
-pub enum FlowControl {
-    Continue,
-    Break,
-    Return(Option<Expression>),
-}
-
-#[derive(Debug, Clone, PartialEq, Default)]
-pub struct Block {
-    pub statements: Vec<Statement<StatementKind>>,
-}
-
-impl From<Vec<Statement<StatementKind>>> for Block {
-    fn from(statements: Vec<Statement<StatementKind>>) -> Self {
-        Self { statements }
-    }
-}
-
-impl From<Statement<StatementKind>> for Block {
-    fn from(statement: Statement<StatementKind>) -> Self {
-        Self { statements: vec![statement] }
-    }
-}
-
-impl AsRef<[Statement<StatementKind>]> for Block {
-    fn as_ref(&self) -> &[Statement<StatementKind>] {
-        self.statements.as_ref()
-    }
-}
-
-pub type ParamName = Rc<String>;
-
-#[derive(Debug, Derivative, Clone)]
-#[derivative(PartialEq)]
-pub struct QualifiedName {
-    #[derivative(PartialEq = "ignore")]
-    pub id: ItemId,
-    pub components: Vec<Rc<String>>,
-}
-
-impl fmt::Display for QualifiedName {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        match &self.components[..] {
-            [] => write!(f, "[<empty>]"),
-            [name] => write!(f, "{}", name),
-            [name, rest @ ..] => {
-                write!(f, "{}", name)?;
-                for c in rest {
-                    write!(f, "::{}", c)?;
-                }
-                Ok(())
-            }
-        }
-    }
-}
-
-#[derive(Debug, PartialEq, Clone)]
-pub struct FormalParam {
-    pub name: ParamName,
-    pub default: Option<Expression>,
-    pub anno: Option<TypeIdentifier>,
-}
-
-#[derive(Debug, PartialEq, Clone)]
-pub enum Declaration {
-    FuncSig(Signature),
-    FuncDecl(Signature, Block),
-    TypeDecl {
-        name: TypeSingletonName,
-        body: TypeBody,
-        mutable: bool,
-    },
-    //TODO TypeAlias `original` needs to be a more complex type definition
-    TypeAlias {
-        alias: Rc<String>,
-        original: Rc<String>,
-    },
-    Binding {
-        name: Rc<String>,
-        constant: bool,
-        type_anno: Option<TypeIdentifier>,
-        expr: Expression,
-    },
-    Impl {
-        type_name: TypeIdentifier,
-        interface_name: Option<TypeSingletonName>,
-        block: Vec<Statement<Declaration>>,
-    },
-    Interface {
-        name: Rc<String>,
-        signatures: Vec<Signature>,
-    },
-    //TODO need to limit the types of statements that can be annotated
-    Annotation {
-        name: Rc<String>,
-        arguments: Vec<Expression>,
-        inner: Box<Statement<StatementKind>>,
-    },
-    Module {
-        name: Rc<String>,
-        items: Block,
-    },
-}
-
-#[derive(Debug, PartialEq, Clone)]
-pub struct Signature {
-    pub name: Rc<String>,
-    pub operator: bool,
-    pub params: Vec<FormalParam>,
-    pub type_anno: Option<TypeIdentifier>,
-}
-
-//TODO I can probably get rid of TypeBody
-#[derive(Debug, Derivative, Clone)]
-#[derivative(PartialEq)]
-pub enum TypeBody {
-    Variants(Vec<Variant>),
-    ImmediateRecord {
-        #[derivative(PartialEq = "ignore")]
-        id: ItemId,
-        fields: Vec<(Rc<String>, TypeIdentifier)>,
-    },
-}
-
-#[derive(Debug, Derivative, Clone)]
-#[derivative(PartialEq)]
-pub struct Variant {
-    #[derivative(PartialEq = "ignore")]
-    pub id: ItemId,
-    pub name: Rc<String>,
-    pub kind: VariantKind,
-}
-
-#[derive(Debug, PartialEq, Clone)]
-pub enum VariantKind {
-    UnitStruct,
-    TupleStruct(Vec<TypeIdentifier>),
-    Record(Vec<(Rc<String>, TypeIdentifier)>),
-}
-
-#[derive(Debug, Derivative, Clone)]
-#[derivative(PartialEq)]
-pub struct Expression {
-    #[derivative(PartialEq = "ignore")]
-    pub id: ItemId,
-    pub kind: ExpressionKind,
-    //TODO this should only allow singletons, not tuples
-    pub type_anno: Option<TypeIdentifier>,
-}
-
-impl Expression {
-    pub fn new(id: ItemId, kind: ExpressionKind) -> Expression {
-        Expression { id, kind, type_anno: None }
-    }
-}
-
-#[derive(Debug, PartialEq, Clone)]
-pub enum TypeIdentifier {
-    Tuple(Vec<TypeIdentifier>),
-    Singleton(TypeSingletonName),
-}
-
-impl fmt::Display for TypeIdentifier {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        match self {
-            TypeIdentifier::Tuple(items) =>
-                write!(f, "{}", delim_wrapped('(', ')', items.iter().map(|item| item.to_string()))),
-            TypeIdentifier::Singleton(tsn) => {
-                write!(f, "{}", tsn.name)?;
-                if !tsn.params.is_empty() {
-                    write!(f, "{}", delim_wrapped('<', '>', tsn.params.iter().map(|item| item.to_string())))?;
-                }
-                Ok(())
-            }
-        }
-    }
-}
-
-#[derive(Debug, PartialEq, Clone)]
-pub struct TypeSingletonName {
-    pub name: Rc<String>,
-    pub params: Vec<TypeIdentifier>,
-}
-
-#[derive(Debug, PartialEq, Clone)]
-pub enum ExpressionKind {
-    NatLiteral(u64),
-    FloatLiteral(f64),
-    StringLiteral { prefix: Option<Rc<String>>, s: Rc<String> },
-    BoolLiteral(bool),
-    BinExp(BinOp, Box<Expression>, Box<Expression>),
-    PrefixExp(PrefixOp, Box<Expression>),
-    TupleLiteral(Vec<Expression>),
-    Value(QualifiedName),
-    SelfValue,
-    NamedStruct { name: QualifiedName, fields: Vec<(Rc<String>, Expression)> },
-    Call { f: Box<Expression>, arguments: Vec<InvocationArgument> },
-    Index { indexee: Box<Expression>, indexers: Vec<Expression> },
-    IfExpression { discriminator: Option<Box<Expression>>, body: Box<IfExpressionBody> },
-    WhileExpression { condition: Option<Box<Expression>>, body: Block },
-    ForExpression { enumerators: Vec<Enumerator>, body: Box<ForBody> },
-    Lambda { params: Vec<FormalParam>, type_anno: Option<TypeIdentifier>, body: Block },
-    Access { name: Rc<String>, expr: Box<Expression> },
-    ListLiteral(Vec<Expression>),
-}
-
-#[derive(Debug, PartialEq, Clone)]
-pub enum InvocationArgument {
-    Positional(Expression),
-    Keyword { name: Rc<String>, expr: Expression },
-    Ignored,
-}
-
-#[derive(Debug, PartialEq, Clone)]
-pub enum IfExpressionBody {
-    SimpleConditional { then_case: Block, else_case: Option<Block> },
-    SimplePatternMatch { pattern: Pattern, then_case: Block, else_case: Option<Block> },
-    CondList(Vec<ConditionArm>),
-}
-
-#[derive(Debug, PartialEq, Clone)]
-pub struct ConditionArm {
-    pub condition: Condition,
-    pub guard: Option<Expression>,
-    pub body: Block,
-}
-
-#[derive(Debug, PartialEq, Clone)]
-pub enum Condition {
-    Pattern(Pattern),
-    TruncatedOp(BinOp, Expression),
-    //Expression(Expression), //I'm pretty sure I don't actually want this
-    Else,
-}
-
-#[derive(Debug, PartialEq, Clone)]
-pub enum Pattern {
-    Ignored,
-    TuplePattern(Vec<Pattern>),
-    Literal(PatternLiteral),
-    TupleStruct(QualifiedName, Vec<Pattern>),
-    Record(QualifiedName, Vec<(Rc<String>, Pattern)>),
-    VarOrName(QualifiedName),
-}
-
-#[derive(Debug, PartialEq, Clone)]
-pub enum PatternLiteral {
-    NumPattern { neg: bool, num: ExpressionKind },
-    StringPattern(Rc<String>),
-    BoolPattern(bool),
-}
-
-#[derive(Debug, PartialEq, Clone)]
-pub struct Enumerator {
-    pub identifier: Rc<String>,
-    pub generator: Expression,
-    pub assignment: bool, //true if `=`, false if `<-`
-}
-
-#[derive(Debug, PartialEq, Clone)]
-pub enum ForBody {
-    MonadicReturn(Expression),
-    StatementBlock(Block),
-}
-
-#[derive(Debug, Derivative, Clone)]
-#[derivative(PartialEq)]
-pub struct ImportSpecifier {
-    #[derivative(PartialEq = "ignore")]
-    pub id: ItemId,
-    pub path_components: Vec<Rc<String>>,
-    pub imported_names: ImportedNames,
-}
-
-#[derive(Debug, PartialEq, Clone)]
-pub enum ImportedNames {
-    All,
-    LastOfPath,
-    List(Vec<Rc<String>>),
-}
-
-#[derive(Debug, PartialEq, Clone)]
-pub struct ModuleSpecifier {
-    pub name: Rc<String>,
-    pub contents: Block,
-}

schala-lang/src/ast/operators.rs

@@ -1,61 +0,0 @@
-use std::rc::Rc;
-
-#[derive(Debug, PartialEq, Clone)]
-pub struct PrefixOp {
-    sigil: Rc<String>,
-}
-
-impl PrefixOp {
-    pub fn from_sigil(sigil: &str) -> PrefixOp {
-        PrefixOp { sigil: Rc::new(sigil.to_string()) }
-    }
-
-    pub fn sigil(&self) -> &str {
-        &self.sigil
-    }
-}
-
-#[derive(Debug, PartialEq, Clone)]
-pub struct BinOp {
-    sigil: Rc<String>,
-}
-
-impl BinOp {
-    pub fn from_sigil(sigil: &str) -> BinOp {
-        BinOp { sigil: Rc::new(sigil.to_string()) }
-    }
-
-    pub fn sigil(&self) -> &str {
-        &self.sigil
-    }
-
-    pub fn min_precedence() -> i32 {
-        i32::min_value()
-    }
-    pub fn get_precedence(&self) -> i32 {
-        binop_precedences(self.sigil.as_ref())
-    }
-}
-
-fn binop_precedences(s: &str) -> i32 {
-    let default = 10_000_000;
-    match s {
-        "+" => 10,
-        "-" => 10,
-        "*" => 20,
-        "/" => 20,
-        "%" => 20,
-        "++" => 30,
-        "^" => 30,
-        "&" => 20,
-        "|" => 20,
-        ">" => 20,
-        ">=" => 20,
-        "<" => 20,
-        "<=" => 20,
-        "==" => 40,
-        "<=>" => 30,
-        "=" => 5, // Assignment shoudl have highest precedence
-        _ => default,
-    }
-}

schala-lang/src/ast/visitor.rs

@@ -1,202 +0,0 @@
-use crate::ast::*;
-
-#[derive(Debug)]
-pub enum Recursion {
-    Continue,
-    Stop,
-}
-
-pub trait ASTVisitor: Sized {
-    fn expression(&mut self, _expression: &Expression) -> Recursion {
-        Recursion::Continue
-    }
-    fn declaration(&mut self, _declaration: &Declaration, _id: &ItemId) -> Recursion {
-        Recursion::Continue
-    }
-
-    fn import(&mut self, _import: &ImportSpecifier) -> Recursion {
-        Recursion::Continue
-    }
-    fn pattern(&mut self, _pat: &Pattern) -> Recursion {
-        Recursion::Continue
-    }
-}
-
-pub fn walk_ast<V: ASTVisitor>(v: &mut V, ast: &AST) {
-    walk_block(v, &ast.statements);
-}
-
-pub fn walk_block<V: ASTVisitor>(v: &mut V, block: &Block) {
-    use StatementKind::*;
-    for statement in block.statements.iter() {
-        match statement.kind {
-            StatementKind::Expression(ref expr) => {
-                walk_expression(v, expr);
-            }
-            Declaration(ref decl) => {
-                walk_declaration(v, decl, &statement.id);
-            }
-            Import(ref import_spec) => {
-                v.import(import_spec);
-            }
-            Flow(ref flow_control) =>
-                if let FlowControl::Return(Some(ref retval)) = flow_control {
-                    walk_expression(v, retval);
-                },
-        }
-    }
-}
-
-pub fn walk_declaration<V: ASTVisitor>(v: &mut V, decl: &Declaration, id: &ItemId) {
-    use Declaration::*;
-
-    if let Recursion::Continue = v.declaration(decl, id) {
-        match decl {
-            FuncDecl(_sig, block) => {
-                walk_block(v, block);
-            }
-            Binding { name: _, constant: _, type_anno: _, expr } => {
-                walk_expression(v, expr);
-            }
-            Module { name: _, items } => {
-                walk_block(v, items);
-            }
-            _ => (),
-        };
-    }
-}
-
-pub fn walk_expression<V: ASTVisitor>(v: &mut V, expr: &Expression) {
-    use ExpressionKind::*;
-
-    if let Recursion::Continue = v.expression(expr) {
-        match &expr.kind {
-            NatLiteral(_)
-            | FloatLiteral(_)
-            | StringLiteral { .. }
-            | BoolLiteral(_)
-            | Value(_)
-            | SelfValue => (),
-            BinExp(_, lhs, rhs) => {
-                walk_expression(v, lhs);
-                walk_expression(v, rhs);
-            }
-            PrefixExp(_, arg) => {
-                walk_expression(v, arg);
-            }
-            TupleLiteral(exprs) =>
-                for expr in exprs {
-                    walk_expression(v, expr);
-                },
-            NamedStruct { name: _, fields } =>
-                for (_, expr) in fields.iter() {
-                    walk_expression(v, expr);
-                },
-            Call { f, arguments } => {
-                walk_expression(v, f);
-                for arg in arguments.iter() {
-                    match arg {
-                        InvocationArgument::Positional(expr) | InvocationArgument::Keyword { expr, .. } =>
-                            walk_expression(v, expr),
-                        _ => (),
-                    }
-                }
-            }
-            Index { indexee, indexers } => {
-                walk_expression(v, indexee);
-                for indexer in indexers.iter() {
-                    walk_expression(v, indexer);
-                }
-            }
-            IfExpression { discriminator, body } => {
-                if let Some(d) = discriminator.as_ref() {
-                    walk_expression(v, d);
-                }
-                walk_if_expr_body(v, body.as_ref());
-            }
-            WhileExpression { condition, body } => {
-                if let Some(d) = condition.as_ref() {
-                    walk_expression(v, d);
-                }
-                walk_block(v, body);
-            }
-            ForExpression { enumerators, body } => {
-                for enumerator in enumerators {
-                    walk_expression(v, &enumerator.generator);
-                }
-                match body.as_ref() {
-                    ForBody::MonadicReturn(expr) => walk_expression(v, expr),
-                    ForBody::StatementBlock(block) => walk_block(v, block),
-                };
-            }
-            Lambda { params: _, type_anno: _, body } => {
-                walk_block(v, body);
-            }
-            Access { name: _, expr } => {
-                walk_expression(v, expr);
-            }
-            ListLiteral(exprs) =>
-                for expr in exprs {
-                    walk_expression(v, expr);
-                },
-        };
-    }
-}
-
-pub fn walk_if_expr_body<V: ASTVisitor>(v: &mut V, body: &IfExpressionBody) {
-    use IfExpressionBody::*;
-
-    match body {
-        SimpleConditional { then_case, else_case } => {
-            walk_block(v, then_case);
-            if let Some(block) = else_case.as_ref() {
-                walk_block(v, block)
-            }
-        }
-        SimplePatternMatch { pattern, then_case, else_case } => {
-            walk_pattern(v, pattern);
-            walk_block(v, then_case);
-            if let Some(block) = else_case.as_ref() {
-                walk_block(v, block)
-            }
-        }
-        CondList(arms) =>
-            for arm in arms {
-                match arm.condition {
-                    Condition::Pattern(ref pat) => {
-                        walk_pattern(v, pat);
-                    }
-                    Condition::TruncatedOp(ref _binop, ref expr) => {
-                        walk_expression(v, expr);
-                    }
-                    Condition::Else => (),
-                }
-                if let Some(ref guard) = arm.guard {
-                    walk_expression(v, guard);
-                }
-                walk_block(v, &arm.body);
-            },
-    }
-}
-
-pub fn walk_pattern<V: ASTVisitor>(v: &mut V, pat: &Pattern) {
-    use Pattern::*;
-
-    if let Recursion::Continue = v.pattern(pat) {
-        match pat {
-            TuplePattern(patterns) =>
-                for pat in patterns {
-                    walk_pattern(v, pat);
-                },
-            TupleStruct(_, patterns) =>
-                for pat in patterns {
-                    walk_pattern(v, pat);
-                },
-            Record(_, name_and_patterns) =>
-                for (_, pat) in name_and_patterns {
-                    walk_pattern(v, pat);
-                },
-            _ => (),
-        };
-    }
-}

schala-lang/src/ast/visualize.rs

@@ -1,282 +0,0 @@
-#![allow(clippy::single_char_add_str)]
-use std::fmt::Write;
-
-use super::{
-    Block, Declaration, Expression, ExpressionKind, FlowControl, ImportSpecifier, InvocationArgument,
-    Signature, Statement, StatementKind, AST,
-};
-
-const LEVEL: usize = 2;
-
-fn do_indent(n: usize, buf: &mut String) {
-    for _ in 0..n {
-        buf.push(' ');
-    }
-}
-
-fn newline(buf: &mut String) {
-    buf.push('\n');
-}
-
-pub(super) fn render_ast(ast: &AST) -> String {
-    let AST { statements, .. } = ast;
-
-    let mut buf = "(AST\n".to_string();
-    render_block(statements, LEVEL, &mut buf);
-
-    buf.push(')');
-
-    buf
-}
-
-fn render_statement(stmt: &Statement<StatementKind>, indent: usize, buf: &mut String) {
-    use StatementKind::*;
-    do_indent(indent, buf);
-    match stmt.kind {
-        Expression(ref expr) => render_expression(expr, indent, buf),
-        Declaration(ref decl) => render_declaration(decl, indent, buf),
-        Import(ref spec) => render_import(spec, indent, buf),
-        Flow(ref flow_control) => render_flow_control(flow_control, indent, buf),
-    }
-}
-
-fn render_expression(expr: &Expression, indent: usize, buf: &mut String) {
-    use ExpressionKind::*;
-
-    buf.push_str("(Expr ");
-    match &expr.kind {
-        SelfValue => write!(buf, "(SelfValue)").unwrap(),
-        NatLiteral(n) => buf.push_str(&format!("(NatLiteral {})", n)),
-        FloatLiteral(f) => buf.push_str(&format!("(FloatLiteral {})", f)),
-        StringLiteral { s, prefix } => buf.push_str(&format!("(StringLiteral prefix: {:?} {})", prefix, s)),
-        BoolLiteral(b) => buf.push_str(&format!("(BoolLiteral {})", b)),
-        BinExp(binop, lhs, rhs) => {
-            let new_indent = indent + LEVEL;
-            buf.push_str(&format!("Binop {}\n", binop.sigil()));
-
-            do_indent(new_indent, buf);
-            render_expression(lhs, new_indent, buf);
-            newline(buf);
-
-            do_indent(new_indent, buf);
-            render_expression(rhs, new_indent, buf);
-            newline(buf);
-
-            do_indent(indent, buf);
-        }
-        PrefixExp(prefix, expr) => {
-            let new_indent = indent + LEVEL;
-            buf.push_str(&format!("PrefixOp {}\n", prefix.sigil()));
-
-            do_indent(new_indent, buf);
-            render_expression(expr, new_indent, buf);
-            newline(buf);
-
-            do_indent(indent, buf);
-        }
-        TupleLiteral(..) => (),
-        Value(name) => {
-            buf.push_str(&format!("Value {})", name));
-        }
-        NamedStruct { name: _, fields: _ } => (),
-        Call { f, arguments } => {
-            let new_indent = indent + LEVEL;
-            buf.push_str("Call ");
-            render_expression(f, new_indent, buf);
-            newline(buf);
-
-            for arg in arguments {
-                do_indent(new_indent, buf);
-                match arg {
-                    InvocationArgument::Positional(expr) => render_expression(expr, new_indent, buf),
-                    InvocationArgument::Keyword { .. } => buf.push_str("<keyword>"),
-                    InvocationArgument::Ignored => buf.push_str("<ignored>"),
-                }
-                newline(buf);
-                do_indent(indent, buf);
-            }
-        }
-        Index { .. } => buf.push_str("<index>"),
-        IfExpression { .. } => buf.push_str("<if-expr>"),
-        WhileExpression { .. } => buf.push_str("<while-expr>"),
-        ForExpression { .. } => buf.push_str("<for-expr>"),
-        Lambda { params, type_anno: _, body } => {
-            let new_indent = indent + LEVEL;
-            buf.push_str("Lambda ");
-            newline(buf);
-
-            do_indent(new_indent, buf);
-            buf.push_str("(Args ");
-            for p in params {
-                buf.push_str(&format!("{} ", p.name));
-            }
-            buf.push(')');
-            newline(buf);
-
-            do_indent(new_indent, buf);
-            buf.push_str("(Body ");
-            newline(buf);
-            render_block(body, new_indent + LEVEL, buf);
-            do_indent(new_indent, buf);
-            buf.push(')');
-
-            newline(buf);
-            do_indent(indent, buf);
-        }
-        Access { .. } => buf.push_str("<access-expr>"),
-        ListLiteral(..) => buf.push_str("<list-literal>"),
-    }
-    buf.push(')');
-}
-fn render_declaration(decl: &Declaration, indent: usize, buf: &mut String) {
-    use Declaration::*;
-
-    buf.push_str("(Decl ");
-    match decl {
-        FuncSig(ref sig) => render_signature(sig, indent, buf),
-        FuncDecl(ref sig, ref block) => {
-            let indent = indent + LEVEL;
-            buf.push_str("Function");
-            newline(buf);
-
-            do_indent(indent, buf);
-            render_signature(sig, indent, buf);
-            newline(buf);
-
-            do_indent(indent, buf);
-            buf.push_str("(Body");
-            newline(buf);
-
-            render_block(block, indent + LEVEL, buf);
-            do_indent(indent, buf);
-            buf.push_str(")");
-            newline(buf);
-        }
-        TypeDecl { name: _, body: _, .. } => {
-            buf.push_str("<type-decl>");
-        }
-        TypeAlias { alias: _, original: _ } => {
-            buf.push_str("<type-alias>");
-        }
-        Binding { name, constant: _, type_anno: _, expr } => {
-            let new_indent = indent + LEVEL;
-            buf.push_str(&format!("Binding {}", name));
-            newline(buf);
-            do_indent(new_indent, buf);
-            render_expression(expr, new_indent, buf);
-            newline(buf);
-        }
-        Module { name, items: _ } => {
-            write!(buf, "(Module {} <body>)", name).unwrap();
-        }
-        _ => (), /*
-                 Impl { type_name: TypeIdentifier, interface_name: Option<TypeSingletonName>, block: Vec<Declaration> },
-                 Interface { name: Rc<String>, signatures: Vec<Signature> },
-                 Annotation { name: Rc<String>, arguments: Vec<Expression> },
-                     */
-    }
-    do_indent(indent, buf);
-    buf.push(')');
-}
-
-fn render_block(block: &Block, indent: usize, buf: &mut String) {
-    for stmt in block.statements.iter() {
-        render_statement(stmt, indent, buf);
-        newline(buf);
-    }
-}
-
-fn render_signature(sig: &Signature, _indent: usize, buf: &mut String) {
-    buf.push_str(&format!("(Signature {} )", sig.name));
-}
-
-fn render_import(_import: &ImportSpecifier, _indent: usize, buf: &mut String) {
-    buf.push_str("(Import <some import>)");
-}
-
-fn render_flow_control(flow: &FlowControl, _indent: usize, buf: &mut String) {
-    use FlowControl::*;
-    match flow {
-        Return(ref _expr) => write!(buf, "return <expr>").unwrap(),
-        Break => write!(buf, "break").unwrap(),
-        Continue => write!(buf, "continue").unwrap(),
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use super::render_ast;
-    use crate::util::quick_ast;
-
-    #[test]
-    fn test_visualization() {
-        let ast = quick_ast(
-            r#"
-    fn test(x) {
-        let m = 9
-        1 * 4 <> m |> somemod::output(x)
-    }
-
-    let quincy = \(no, yes, maybe) {
-        let a = 10
-        yes * no + a
-    }
-
-    let b = 54
-    test(b) == 3
-    "#,
-        );
-
-        let expected_output = r#"(AST
-  (Decl Function
-    (Signature test )
-    (Body
-      (Decl Binding m
-        (Expr (NatLiteral 9))
-      )
-      (Expr Binop *
-        (Expr (NatLiteral 1))
-        (Expr Binop |>
-          (Expr Binop <>
-            (Expr (NatLiteral 4))
-            (Expr Value m))
-          )
-          (Expr Call (Expr Value somemod::output))
-            (Expr Value x))
-          )
-        )
-      )
-    )
-  )
-  (Decl Binding quincy
-    (Expr Lambda 
-      (Args no yes maybe )
-      (Body 
-        (Decl Binding a
-          (Expr (NatLiteral 10))
-        )
-        (Expr Binop +
-          (Expr Binop *
-            (Expr Value yes))
-            (Expr Value no))
-          )
-          (Expr Value a))
-        )
-      )
-    )
-  )
-  (Decl Binding b
-    (Expr (NatLiteral 54))
-  )
-  (Expr Binop ==
-    (Expr Call (Expr Value test))
-      (Expr Value b))
-    )
-    (Expr (NatLiteral 3))
-  )
-)"#;
-
-        let rendered = render_ast(&ast);
-        assert_eq!(rendered, expected_output);
-    }
-}

schala-lang/src/builtin.rs

@@ -1,130 +0,0 @@
-use std::{convert::TryFrom, str::FromStr};
-
-use crate::{
-    ast::{BinOp, PrefixOp},
-    type_inference::Type,
-};
-
-/// "Builtin" computational operations with some kind of semantics, mostly mathematical operations.
-#[derive(Debug, Clone, Copy, PartialEq)]
-pub enum Builtin {
-    Add,
-    Increment,
-    Subtract,
-    Negate,
-    Multiply,
-    Divide,
-    Quotient,
-    Modulo,
-    Exponentiation,
-    BitwiseAnd,
-    BitwiseOr,
-    BooleanAnd,
-    BooleanOr,
-    BooleanNot,
-    Equality,
-    LessThan,
-    LessThanOrEqual,
-    GreaterThan,
-    GreaterThanOrEqual,
-    Comparison,
-    IOPrint,
-    IOPrintLn,
-    IOGetLine,
-    Assignment,
-    Concatenate,
-    NotEqual,
-}
-
-impl Builtin {
-    #[allow(dead_code)]
-    pub fn get_type(&self) -> Type {
-        use Builtin::*;
-        match self {
-            Add => ty!(Nat -> Nat -> Nat),
-            Subtract => ty!(Nat -> Nat -> Nat),
-            Multiply => ty!(Nat -> Nat -> Nat),
-            Divide => ty!(Nat -> Nat -> Float),
-            Quotient => ty!(Nat -> Nat -> Nat),
-            Modulo => ty!(Nat -> Nat -> Nat),
-            Exponentiation => ty!(Nat -> Nat -> Nat),
-            BitwiseAnd => ty!(Nat -> Nat -> Nat),
-            BitwiseOr => ty!(Nat -> Nat -> Nat),
-            BooleanAnd => ty!(Bool -> Bool -> Bool),
-            BooleanOr => ty!(Bool -> Bool -> Bool),
-            BooleanNot => ty!(Bool -> Bool),
-            Equality => ty!(Nat -> Nat -> Bool),
-            LessThan => ty!(Nat -> Nat -> Bool),
-            LessThanOrEqual => ty!(Nat -> Nat -> Bool),
-            GreaterThan => ty!(Nat -> Nat -> Bool),
-            GreaterThanOrEqual => ty!(Nat -> Nat -> Bool),
-            Comparison => ty!(Nat -> Nat -> Ordering),
-            IOPrint => ty!(Unit),
-            IOPrintLn => ty!(Unit),
-            IOGetLine => ty!(StringT),
-            Assignment => ty!(Unit),
-            Concatenate => ty!(StringT -> StringT -> StringT),
-            Increment => ty!(Nat -> Int),
-            Negate => ty!(Nat -> Int),
-            NotEqual => ty!(Nat -> Nat -> Bool),
-        }
-    }
-}
-
-impl TryFrom<&BinOp> for Builtin {
-    type Error = ();
-
-    fn try_from(binop: &BinOp) -> Result<Self, Self::Error> {
-        FromStr::from_str(binop.sigil())
-    }
-}
-
-impl TryFrom<&PrefixOp> for Builtin {
-    type Error = ();
-
-    fn try_from(prefix_op: &PrefixOp) -> Result<Self, Self::Error> {
-        use Builtin::*;
-
-        match prefix_op.sigil() {
-            "+" => Ok(Increment),
-            "-" => Ok(Negate),
-            "!" => Ok(BooleanNot),
-            _ => Err(()),
-        }
-    }
-}
-
-impl FromStr for Builtin {
-    type Err = ();
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        use Builtin::*;
-        Ok(match s {
-            "+" => Add,
-            "-" => Subtract,
-            "*" => Multiply,
-            "/" => Divide,
-            "quot" => Quotient,
-            "%" => Modulo,
-            "++" => Concatenate,
-            "^" => Exponentiation,
-            "&" => BitwiseAnd,
-            "&&" => BooleanAnd,
-            "|" => BitwiseOr,
-            "||" => BooleanOr,
-            "!" => BooleanNot,
-            ">" => GreaterThan,
-            ">=" => GreaterThanOrEqual,
-            "<" => LessThan,
-            "<=" => LessThanOrEqual,
-            "==" => Equality,
-            "!=" => NotEqual,
-            "=" => Assignment,
-            "<=>" => Comparison,
-            "print" => IOPrint,
-            "println" => IOPrintLn,
-            "getline" => IOGetLine,
-            _ => return Err(()),
-        })
-    }
-}

schala-lang/src/error.rs

@@ -1,79 +0,0 @@
-use crate::{
-    parsing::{Location, ParseError},
-    schala::{SourceReference, Stage},
-    symbol_table::SymbolError,
-    type_inference::TypeError,
-};
-
-pub struct SchalaError {
-    errors: Vec<Error>,
-}
-
-impl SchalaError {
-    pub(crate) fn display(&self) -> String {
-        match self.errors[0] {
-            Error::Parse(ref parse_err) => parse_err.to_string(),
-            Error::Standard { ref text, .. } => text.as_ref().cloned().unwrap_or_default(),
-        }
-    }
-
-    #[allow(dead_code)]
-    pub(crate) fn from_type_error(err: TypeError) -> Self {
-        Self {
-            errors: vec![Error::Standard { location: None, text: Some(err.msg), stage: Stage::Typechecking }],
-        }
-    }
-
-    pub(crate) fn from_symbol_table(symbol_errs: Vec<SymbolError>) -> Self {
-        //TODO this could be better
-        let errors = symbol_errs
-            .into_iter()
-            .map(|_symbol_err| Error::Standard {
-                location: None,
-                text: Some("symbol table error".to_string()),
-                stage: Stage::Symbols,
-            })
-            .collect();
-        Self { errors }
-    }
-
-    pub(crate) fn from_string(text: String, stage: Stage) -> Self {
-        Self { errors: vec![Error::Standard { location: None, text: Some(text), stage }] }
-    }
-
-    pub(crate) fn from_parse_error(parse_error: ParseError, source_reference: &SourceReference) -> Self {
-        let formatted_parse_error = format_parse_error(parse_error, source_reference);
-        Self { errors: vec![Error::Parse(formatted_parse_error)] }
-    }
-}
-
-#[allow(dead_code)]
-enum Error {
-    Standard { location: Option<Location>, text: Option<String>, stage: Stage },
-    Parse(String),
-}
-
-fn format_parse_error(error: ParseError, source_reference: &SourceReference) -> String {
-    let offset = error.location.offset;
-    let (line_start, line_num, line_from_program) = source_reference.get_line(offset);
-    let ch = offset - line_start;
-
-    let location_pointer = format!("{}^", " ".repeat(ch));
-
-    let line_num_digits = format!("{}", line_num).chars().count();
-    let space_padding = " ".repeat(line_num_digits);
-
-    format!(
-        r#"
-{error_msg}
-{space_padding} |
-{line_num} | {}
-{space_padding} | {}
-"#,
-        line_from_program,
-        location_pointer,
-        error_msg = error.msg,
-        space_padding = space_padding,
-        line_num = line_num,
-    )
-}

schala-lang/src/identifier.rs

@@ -1,75 +0,0 @@
-use std::{
-    fmt::{self, Debug},
-    hash::Hash,
-    marker::PhantomData,
-};
-
-pub trait IdKind: Debug + Copy + Clone + Hash + PartialEq + Eq + Default {
-    fn tag() -> &'static str;
-}
-
-/// A generalized abstract identifier type of up to 2^32-1 entries.
-#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq, Default)]
-pub struct Id<T>
-where T: IdKind
-{
-    idx: u32,
-    t: PhantomData<T>,
-}
-
-impl<T> Id<T>
-where T: IdKind
-{
-    fn new(n: u32) -> Self {
-        Self { idx: n, t: PhantomData }
-    }
-
-    #[allow(dead_code)]
-    pub fn as_u32(&self) -> u32 {
-        self.idx
-    }
-}
-
-impl<T> fmt::Display for Id<T>
-where T: IdKind
-{
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "{}:{}", self.idx, T::tag())
-    }
-}
-
-#[derive(Debug)]
-pub struct IdStore<T>
-where T: IdKind
-{
-    last_idx: u32,
-    t: PhantomData<T>,
-}
-
-impl<T> IdStore<T>
-where T: IdKind
-{
-    pub fn new() -> Self {
-        Self { last_idx: 0, t: PhantomData }
-    }
-
-    pub fn fresh(&mut self) -> Id<T> {
-        let idx = self.last_idx;
-        self.last_idx += 1;
-        Id::new(idx)
-    }
-}
-
-macro_rules! define_id_kind {
-    ($name:ident) => {
-        #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq, Default)]
-        pub struct $name;
-        impl crate::identifier::IdKind for $name {
-            fn tag() -> &'static str {
-                stringify!($name)
-            }
-        }
-    };
-}
-
-pub(crate) use define_id_kind;

schala-lang/src/lib.rs

@@ -1,31 +0,0 @@
-#![feature(trace_macros)]
-//#![feature(unrestricted_attribute_tokens)]
-#![feature(box_patterns, iter_intersperse)]
-
-//! `schala-lang` is where the Schala programming language is actually implemented.
-//! It defines the `Schala` type, which contains the state for a Schala REPL, and implements
-//! `ProgrammingLanguageInterface` and the chain of compiler passes for it.
-
-extern crate derivative;
-extern crate schala_repl;
-
-#[macro_use]
-mod util;
-
-#[macro_use]
-mod type_inference;
-
-mod ast;
-mod parsing;
-#[macro_use]
-mod symbol_table;
-mod builtin;
-mod error;
-mod reduced_ir;
-mod tree_walk_eval;
-#[macro_use]
-mod identifier;
-
-mod schala;
-
-pub use schala::{Schala, SchalaConfig};

schala-lang/src/parsing/mod.rs

@@ -1,126 +0,0 @@
-#![allow(clippy::upper_case_acronyms)]
-
-pub mod combinator;
-mod peg_parser;
-mod test;
-
-use std::{cell::RefCell, fmt, rc::Rc};
-
-use combinator::Span;
-
-#[cfg(test)]
-use crate::ast::{Block, Expression};
-use crate::{
-    ast::{ASTItem, AST},
-    identifier::{Id, IdStore},
-};
-
-pub(crate) type StoreRef = Rc<RefCell<IdStore<ASTItem>>>;
-pub struct Parser {
-    id_store: StoreRef,
-    use_combinator: bool,
-}
-
-impl Parser {
-    pub(crate) fn new() -> Self {
-        let id_store: IdStore<ASTItem> = IdStore::new();
-        Self { id_store: Rc::new(RefCell::new(id_store)), use_combinator: true }
-    }
-    pub(crate) fn parse(&mut self, input: &str) -> Result<AST, ParseError> {
-        if self.use_combinator {
-            self.parse_comb(input)
-        } else {
-            self.parse_peg(input)
-        }
-    }
-
-    pub(crate) fn parse_peg(&mut self, input: &str) -> Result<AST, ParseError> {
-        peg_parser::schala_parser::program(input, self).map_err(ParseError::from_peg)
-    }
-
-    pub(crate) fn parse_comb(&mut self, input: &str) -> Result<AST, ParseError> {
-        let span = Span::new_extra(input, self.id_store.clone());
-        convert(input, combinator::program(span))
-    }
-
-    #[cfg(test)]
-    fn expression(&mut self, input: &str) -> Result<Expression, ParseError> {
-        peg_parser::schala_parser::expression(input, self).map_err(ParseError::from_peg)
-    }
-
-    #[cfg(test)]
-    fn expression_comb(&mut self, input: &str) -> Result<Expression, ParseError> {
-        let span = Span::new_extra(input, self.id_store.clone());
-        convert(input, combinator::expression(span))
-    }
-
-    #[cfg(test)]
-    fn block(&mut self, input: &str) -> Result<Block, ParseError> {
-        peg_parser::schala_parser::block(input, self).map_err(ParseError::from_peg)
-    }
-
-    #[cfg(test)]
-    fn block_comb(&mut self, input: &str) -> Result<Block, ParseError> {
-        let span = Span::new_extra(input, self.id_store.clone());
-        convert(input, combinator::block(span))
-    }
-
-    fn fresh(&mut self) -> Id<ASTItem> {
-        self.id_store.borrow_mut().fresh()
-    }
-}
-
-fn convert<'a, O>(input: &'a str, result: combinator::ParseResult<'a, O>) -> Result<O, ParseError> {
-    use nom::{error::VerboseError, Finish};
-
-    match result.finish() {
-        Ok((rest, output)) => {
-            if rest.fragment() != &"" {
-                return Err(ParseError {
-                    location: Default::default(),
-                    msg: format!("Bad parse state, remaining text: `{}`", rest.fragment()),
-                });
-            }
-
-            Ok(output)
-        }
-        Err(err) => {
-            let err = VerboseError {
-                errors: err.errors.into_iter().map(|(sp, kind)| (*sp.fragment(), kind)).collect(),
-            };
-            let msg = nom::error::convert_error(input, err);
-            Err(ParseError { msg, location: (0).into() })
-        }
-    }
-}
-
-/// Represents a parsing error
-#[derive(Debug)]
-pub struct ParseError {
-    pub msg: String,
-    pub location: Location,
-}
-
-impl ParseError {
-    fn from_peg(err: peg::error::ParseError<peg::str::LineCol>) -> Self {
-        let msg = err.to_string();
-        Self { msg, location: err.location.offset.into() }
-    }
-}
-
-#[derive(Debug, Clone, Copy, PartialEq, Default)]
-pub struct Location {
-    pub(crate) offset: usize,
-}
-
-impl From<usize> for Location {
-    fn from(offset: usize) -> Self {
-        Self { offset }
-    }
-}
-
-impl fmt::Display for Location {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "{}", self.offset)
-    }
-}

schala-lang/src/parsing/peg_parser.rs

@@ -1,567 +0,0 @@
-use std::rc::Rc;
-
-use super::Parser;
-use crate::ast::*;
-
-fn rc_string(s: &str) -> Rc<String> {
-    Rc::new(s.to_string())
-}
-
-enum ExtendedPart<'a> {
-    Index(Vec<Expression>),
-    Accessor(&'a str),
-    Call(Vec<InvocationArgument>),
-}
-
-peg::parser! {
-    pub grammar schala_parser() for str {
-
-        rule whitespace() = [' ' | '\t' ]
-        rule whitespace_or_newline() = [' ' | '\t' | '\n' ]
-
-        rule _ = quiet!{ (block_comment() / line_comment() / whitespace())* }
-
-        rule __ = quiet!{ (block_comment() / line_comment() / whitespace_or_newline())* }
-
-        rule block_comment() = "/*" (block_comment() / !"*/" [_])* "*/"
-        rule line_comment() = "//" (!['\n'] [_])* &"\n"
-
-
-        pub rule program(parser: &mut Parser) -> AST =
-            __ statements:(statement(parser) ** (delimiter()+) ) __ { AST { id: parser.fresh(), statements: statements.into() } }
-
-        rule delimiter() = (";" / "\n")+
-
-        //Note - this is a hack, ideally the rule `rule block() -> Block = "{" _ items:(statement() **
-        //delimiter()) _ "}" { items.into() }` would've worked, but it doesn't.
-        pub rule block(parser: &mut Parser) -> Block =
-            "{" __ items:(statement(parser) ** delimiter()) delimiter()? __ "}" { items.into() } /
-            "{" __ stmt:statement(parser) __ "}" { vec![stmt].into() }
-
-        rule block_item(parser: &mut Parser) -> Statement<StatementKind> =
-            _ stmt:statement(parser) _ delimiter()+ { stmt }
-
-        rule statement(parser: &mut Parser) -> Statement<StatementKind> =
-             _ pos:position!() kind:statement_kind(parser) _ { Statement { id: parser.fresh(), location: pos.into(), kind } }
-
-        rule statement_kind(parser: &mut Parser) -> StatementKind =
-            __ import:import(parser) { StatementKind::Import(import) } /
-            __ decl:declaration(parser) { StatementKind::Declaration(decl) } /
-            __ flow:flow(parser) { StatementKind::Flow(flow) } /
-            __ expr:expression(parser) { StatementKind::Expression(expr) }
-
-        rule flow(parser: &mut Parser) -> FlowControl =
-            "continue" { FlowControl::Continue } /
-            "break" { FlowControl::Break } /
-            "return" _ expr:expression(parser)? { FlowControl::Return(expr) }
-
-            //TODO add the ability to rename and exclude imports
-        rule import(parser: &mut Parser) -> ImportSpecifier =
-            "import" _ path_components:path_components() suffix:import_suffix()? {
-                ImportSpecifier {
-                    id: parser.fresh(),
-                    path_components,
-                    imported_names: suffix.unwrap_or(ImportedNames::LastOfPath)
-                }
-            }
-
-        rule path_components() -> Vec<Rc<String>> =
-            "::"? name:identifier() rest:path_component()* {
-                let mut items = vec![rc_string(name)];
-                items.extend(rest.into_iter().map(rc_string));
-                items
-            }
-
-        rule path_component() -> &'input str = "::" ident:identifier() { ident }
-
-        rule import_suffix() -> ImportedNames =
-            "::*" { ImportedNames::All } /
-            "::{" __ names:(identifier() ** (_ "," _)) __ "}" {?
-                if names.is_empty() {
-                    Err("import groups must have at least one item")
-                } else {
-                    Ok(ImportedNames::List(names.into_iter().map(rc_string).collect()))
-                }
-            }
-
-        rule declaration(parser: &mut Parser) -> Declaration =
-            binding(parser) / type_decl(parser) / annotation(parser) / func(parser) / interface(parser) /
-            implementation(parser) / module(parser)
-
-        rule module(parser: &mut Parser) -> Declaration =
-            "module" _ name:identifier() _ items:block(parser) { Declaration::Module { name: rc_string(name), items } }
-
-        rule implementation(parser: &mut Parser) -> Declaration =
-            "impl" _ interface:type_singleton_name() _ "for" _ type_name:type_identifier() _ block:decl_block(parser) {
-                Declaration::Impl { type_name, interface_name: Some(interface), block }
-
-            } /
-            "impl" _ type_name:type_identifier() _ block:decl_block(parser) {
-                Declaration::Impl { type_name, interface_name: None, block }
-            }
-
-        rule decl_block(parser: &mut Parser) -> Vec<Statement<Declaration>> =
-            "{" __ decls:(func_declaration_stmt(parser) ** (delimiter()+)) delimiter()? __ "}" { decls }
-
-        rule func_declaration_stmt(parser: &mut Parser) -> Statement<Declaration> =
-            pos:position!() decl:func_declaration(parser) { Statement { id: parser.fresh(), location: pos.into(), kind: decl } }
-
-        rule interface(parser: &mut Parser) -> Declaration =
-            "interface" _ name:identifier() _ signatures:signature_block(parser) { Declaration::Interface { name: rc_string(name), signatures } }
-
-        rule signature_block(parser: &mut Parser) -> Vec<Signature> =
-            "{" __  signatures:(func_signature(parser) ** (delimiter()+)) __ "}" { signatures }
-
-        rule func(parser: &mut Parser) -> Declaration =
-            decl:func_declaration(parser) { decl } /
-            sig:func_signature(parser) { Declaration::FuncSig(sig) }
-
-        rule func_declaration(parser: &mut Parser) -> Declaration =
-            _ sig:func_signature(parser) __ body:block(parser) { Declaration::FuncDecl(sig, body) }
-
-        rule func_signature(parser: &mut Parser) -> Signature =
-            _ "fn" _ name:identifier() "(" _ params:formal_params(parser) _ ")" _ type_anno:type_anno()? { Signature {
-                name: rc_string(name), operator: false, params, type_anno
-            } } /
-            _ "fn" _ "(" op:operator() ")" _ "(" _ params:formal_params(parser) _ ")" _ type_anno:type_anno()? { Signature {
-                name: rc_string(op), operator: true, params, type_anno
-            } }
-
-        rule formal_params(parser: &mut Parser) -> Vec<FormalParam> =
-            params:(formal_param(parser) ** (_ "," _)) {? if params.len() < 256 { Ok(params) } else {
-            Err("function-too-long") }
-            }
-
-        rule formal_param(parser: &mut Parser) -> FormalParam =
-            name:identifier() _ anno:type_anno()? _ "=" expr:expression(parser) { FormalParam { name: rc_string(name),
-               default: Some(expr), anno } } /
-            name:identifier() _ anno:type_anno()? { FormalParam { name: rc_string(name), default: None, anno } }
-
-
-        rule annotation(parser: &mut Parser) -> Declaration =
-            "@" name:identifier() args:annotation_args(parser)? delimiter()+ _ inner:statement(parser) { Declaration::Annotation {
-                name: rc_string(name), arguments: if let Some(args) = args { args } else { vec![] }, inner: Box::new(inner) }
-            }
-
-        rule annotation_args(parser: &mut Parser) -> Vec<Expression> =
-            "(" _ args:(expression(parser) ** (_ "," _)) _ ")" { args }
-
-
-        rule binding(parser: &mut Parser) -> Declaration =
-            "let" _ mutable:"mut"? _ ident:identifier() _ type_anno:type_anno()? _ "=" _ expr:expression(parser) {
-                Declaration::Binding { name: Rc::new(ident.to_string()), constant: mutable.is_none(),
-                type_anno, expr }
-            }
-
-
-        rule type_decl(parser: &mut Parser) -> Declaration =
-            "type" _ "alias" _ alias:type_alias() { alias } /
-            "type" _ mutable:"mut"? _ name:type_singleton_name() _ "=" _ body:type_body(parser) {
-                Declaration::TypeDecl { name, body, mutable: mutable.is_some() }
-            }
-
-        rule type_singleton_name() -> TypeSingletonName =
-            name:identifier() params:type_params()? { TypeSingletonName {
-                name: rc_string(name), params: if let Some(params) = params { params } else { vec![] }
-            } }
-
-        rule type_params() -> Vec<TypeIdentifier> =
-            "<" _ idents:(type_identifier() ** (_ "," _)) _ ">" { idents }
-
-        rule type_identifier() -> TypeIdentifier =
-            "(" _ items:(type_identifier() ** (_ "," _)) _ ")" { TypeIdentifier::Tuple(items) } /
-            singleton:type_singleton_name() { TypeIdentifier::Singleton(singleton) }
-
-        rule type_body(parser: &mut Parser) -> TypeBody =
-            "{" _ items:(record_variant_item() ** (__ "," __)) __ "}" { TypeBody::ImmediateRecord { id: parser.fresh(), fields: items } } /
-            variants:(variant_spec(parser) ** (__ "|" __)) { TypeBody::Variants(variants) }
-
-        rule variant_spec(parser: &mut Parser) -> Variant =
-            name:identifier() __ "{" __ typed_identifier_list:(record_variant_item() ** (__ "," __)) __ ","? __ "}" { Variant {
-                id: parser.fresh(), name: rc_string(name), kind: VariantKind::Record(typed_identifier_list)
-            } } /
-            name:identifier() "(" tuple_members:(type_identifier() ++ (__ "," __)) ")" { Variant {
-                id: parser.fresh(), name: rc_string(name), kind: VariantKind::TupleStruct(tuple_members) } } /
-            name:identifier() { Variant { id: parser.fresh(), name: rc_string(name), kind: VariantKind::UnitStruct } }
-
-        rule record_variant_item() -> (Rc<String>, TypeIdentifier) =
-            name:identifier() _ ":" _ ty:type_identifier() { (rc_string(name), ty) }
-
-        rule type_alias() -> Declaration =
-            alias:identifier() _ "=" _ name:identifier() { Declaration::TypeAlias { alias: rc_string(alias), original: rc_string(name), } }
-
-        rule type_anno() -> TypeIdentifier =
-            ":" _ identifier:type_identifier() { identifier }
-
-        pub rule expression(parser: &mut Parser) -> Expression =
-            __ kind:expression_kind(true, parser) _ type_anno:type_anno()? { Expression { id: parser.fresh(), type_anno, kind } }
-
-        rule expression_no_struct(parser: &mut Parser) -> Expression =
-            __ kind:expression_kind(false, parser) { Expression { id: parser.fresh(), type_anno: None, kind } }
-
-        rule expression_kind(struct_ok: bool, parser: &mut Parser) -> ExpressionKind =
-            precedence_expr(struct_ok, parser)
-
-        rule precedence_expr(struct_ok: bool, parser: &mut Parser) -> ExpressionKind =
-        first:prefix_expr(struct_ok, parser) _ next:(precedence_continuation(struct_ok, parser))* {
-            let next = next.into_iter().map(|(sigil, expr)| (BinOp::from_sigil(sigil), expr)).collect();
-            BinopSequence { first, next }.do_precedence(parser)
-        }
-
-        rule precedence_continuation(struct_ok: bool, parser: &mut Parser) -> (&'input str, ExpressionKind) =
-            op:operator() _ expr:prefix_expr(struct_ok, parser) _ { (op, expr) }
-
-        rule prefix_expr(struct_ok: bool, parser: &mut Parser) -> ExpressionKind =
-            prefix:prefix()? expr:extended_expr(struct_ok, parser) {
-                if let Some(p) = prefix {
-                    let expr = Expression::new(parser.fresh(), expr);
-                    let prefix = PrefixOp::from_sigil(p);
-                    ExpressionKind::PrefixExp(prefix, Box::new(expr))
-                } else {
-                    expr
-                }
-            }
-
-
-        rule prefix() -> &'input str =
-            $(['+' | '-' | '!' ])
-
-        //TODO make the definition of operators more complex
-        rule operator() -> &'input str =
-            quiet!{!"*/" s:$( ['+' | '-' | '*' | '/' | '%' | '<' | '>' | '=' | '!' | '$' | '&' | '|' | '?' | '^' | '`']+ ) { s } } /
-            expected!("operator")
-
-        rule extended_expr(struct_ok: bool, parser: &mut Parser) -> ExpressionKind =
-            primary:primary(struct_ok, parser) parts:(extended_expr_part(parser)*) {
-                let mut expression = Expression::new(parser.fresh(), primary);
-                for part in parts.into_iter() {
-                    let kind = match part {
-                        ExtendedPart::Index(indexers) => {
-                            ExpressionKind::Index { indexee: Box::new(expression), indexers }
-                        },
-                        ExtendedPart::Accessor(name) => {
-                            let name = rc_string(name);
-                            ExpressionKind::Access { name, expr: Box::new(expression) }
-                        },
-                        ExtendedPart::Call(arguments) => {
-                            ExpressionKind::Call { f: Box::new(expression), arguments }
-                        }
-                    };
-
-                    expression = Expression::new(parser.fresh(), kind);
-                }
-
-                expression.kind
-            }
-
-        rule extended_expr_part(parser: &mut Parser) -> ExtendedPart<'input> =
-            indexers:index_part(parser) { ExtendedPart::Index(indexers) } /
-            arguments:call_part(parser) { ExtendedPart::Call(arguments) } /
-            "." name:identifier() { ExtendedPart::Accessor(name) }
-
-        rule index_part(parser: &mut Parser) -> Vec<Expression> =
-            "[" indexers:(expression(parser) ++ ",") "]" { indexers }
-
-        rule call_part(parser: &mut Parser) -> Vec<InvocationArgument> =
-            "(" arguments:(invocation_argument(parser) ** ",") ")" { arguments }
-
-        rule invocation_argument(parser: &mut Parser) -> InvocationArgument =
-            _ "_" _ { InvocationArgument::Ignored } /
-            _ ident:identifier() _ "=" _ expr:expression(parser) { InvocationArgument::Keyword {
-                name: Rc::new(ident.to_string()),
-                expr
-                } } /
-            _ expr:expression(parser) _ { InvocationArgument::Positional(expr) }
-
-
-        rule primary(struct_ok: bool, parser: &mut Parser) -> ExpressionKind =
-            while_expr(parser) / for_expr(parser) / float_literal() / nat_literal() / bool_literal() /
-            string_literal() / paren_expr(parser) /
-            list_expr(parser) / if_expr(parser) / lambda_expr(parser) /
-            item:named_struct(parser) {? if struct_ok { Ok(item) } else { Err("no-struct-allowed") } } /
-            identifier_expr(parser)
-
-        rule lambda_expr(parser: &mut Parser) -> ExpressionKind =
-            r#"\"# __ "(" _ params:formal_params(parser) _ ")" _ type_anno:(type_anno()?) _ body:block(parser)  {
-                ExpressionKind::Lambda { params, type_anno, body }
-            } /
-            r#"\"# param:formal_param(parser) _ type_anno:(type_anno()?) _ body:block(parser) {
-                ExpressionKind::Lambda { params: vec![param], type_anno, body }
-            }
-
-        rule for_expr(parser: &mut Parser) -> ExpressionKind =
-            "for" _ enumerators:for_enumerators(parser) _ body:for_body(parser) {
-                ExpressionKind::ForExpression { enumerators, body }
-            }
-
-        rule for_enumerators(parser: &mut Parser) -> Vec<Enumerator> =
-            "{" _ enumerators:(enumerator(parser) ++ ",") _ "}" { enumerators } /
-            enumerator:enumerator(parser) { vec![enumerator] }
-
-        //TODO add guards, etc.
-        rule enumerator(parser: &mut Parser) -> Enumerator =
-            ident:identifier() _ "<-" _ generator:expression_no_struct(parser) {
-                Enumerator { identifier: Rc::new(ident.to_string()), generator, assignment: false }
-            } /
-            //TODO need to distinguish these two cases in AST
-            ident:identifier() _ "=" _ generator:expression_no_struct(parser) {
-                Enumerator { identifier: Rc::new(ident.to_string()), generator, assignment: true }
-            }
-
-        rule for_body(parser: &mut Parser) -> Box<ForBody> =
-            "return" _ expr:expression(parser) { Box::new(ForBody::MonadicReturn(expr)) } /
-            body:block(parser) { Box::new(ForBody::StatementBlock(body)) }
-
-        rule while_expr(parser: &mut Parser) -> ExpressionKind =
-            "while" _ cond:expression_kind(false, parser)? _ body:block(parser) {
-                ExpressionKind::WhileExpression {
-                    condition: cond.map(|kind| Box::new(Expression::new(parser.fresh(), kind))),
-                    body,
-                }
-            }
-
-
-        rule identifier_expr(parser: &mut Parser) -> ExpressionKind =
-            qn:qualified_identifier(parser) { ExpressionKind::Value(qn) }
-
-        rule named_struct(parser: &mut Parser) -> ExpressionKind =
-            name:qualified_identifier(parser) _ fields:record_block(parser) {
-                ExpressionKind::NamedStruct {
-                    name,
-                    fields: fields.into_iter().map(|(n, exp)| (Rc::new(n.to_string()), exp)).collect(),
-                }
-            }
-
-
-        //TODO support anonymous structs and Elm-style update syntax for structs
-        rule record_block(parser: &mut Parser) -> Vec<(&'input str, Expression)> =
-            "{" _ entries:(record_entry(parser) ** ",") _ "}" { entries }
-
-        rule record_entry(parser: &mut Parser) -> (&'input str, Expression) =
-            _ name:identifier() _ ":" _ expr:expression(parser) _ { (name, expr) }
-
-        rule qualified_identifier(parser: &mut Parser) -> QualifiedName =
-            names:(identifier() ++ "::") { QualifiedName { id: parser.fresh(), components: names.into_iter().map(|name| Rc::new(name.to_string())).collect() } }
-
-        //TODO improve the definition of identifiers
-        rule identifier() -> &'input str =
-            !(reserved() !(ident_continuation())) text:$(['a'..='z' | 'A'..='Z' | '_'] ident_continuation()*) { text }
-
-        rule ident_continuation() -> &'input str =
-            text:$(['a'..='z' | 'A'..='Z' | '0'..='9' | '_'])
-
-        rule reserved() = "if" / "then" / "else" / "is" / "fn" / "for" / "while" / "let" / "in" / "mut" / "return" /
-            "break" / "alias" / "type" / "self" / "Self" / "interface" / "impl" / "true" / "false" / "module" / "import"
-
-
-        rule if_expr(parser: &mut Parser) -> ExpressionKind =
-            "if" _ discriminator:(expression(parser)?) _ body:if_expr_body(parser) {
-                ExpressionKind::IfExpression {
-                    discriminator: discriminator.map(Box::new),
-                    body: Box::new(body),
-                }
-            }
-
-        rule if_expr_body(parser: &mut Parser) -> IfExpressionBody =
-            cond_block(parser) / simple_pattern_match(parser) / simple_conditional(parser)
-
-        rule simple_conditional(parser: &mut Parser) -> IfExpressionBody =
-            "then" _ then_case:expr_or_block(parser) _ else_case:else_case(parser) {
-                IfExpressionBody::SimpleConditional { then_case, else_case }
-            }
-
-        rule simple_pattern_match(parser: &mut Parser) -> IfExpressionBody =
-            "is" _ pattern:pattern(parser) _ "then" _ then_case:expr_or_block(parser) _ else_case:else_case(parser) {
-                IfExpressionBody::SimplePatternMatch { pattern, then_case, else_case }
-            }
-
-        rule cond_block(parser: &mut Parser) -> IfExpressionBody =
-            "{" __ cond_arms:(cond_arm(parser) ++ (delimiter()+)) __ "}" { IfExpressionBody::CondList(cond_arms) }
-
-        rule cond_arm(parser: &mut Parser) -> ConditionArm =
-            _ "else" _ body:expr_or_block(parser) { ConditionArm { condition: Condition::Else, guard: None, body } } /
-            _ condition:condition(parser) _ guard:condition_guard(parser) _ "then" _ body:expr_or_block(parser)
-                { ConditionArm { condition, guard, body } }
-
-        rule condition(parser: &mut Parser) -> Condition =
-            "is" _ pat:pattern(parser) { Condition::Pattern(pat) } /
-            op:operator() _ expr:expression(parser) { Condition::TruncatedOp(BinOp::from_sigil(op), expr) }
-
-        rule condition_guard(parser: &mut Parser) -> Option<Expression> =
-            ("if" _ expr:expression(parser) { expr } )?
-
-        rule expr_or_block(parser: &mut Parser) -> Block = block(parser) / pos:position!() ex:expression(parser) {
-            Statement {
-                id: parser.fresh() , location: pos.into(),
-                kind: StatementKind::Expression(ex)
-            }.into()
-        }
-
-        rule else_case(parser: &mut Parser) -> Option<Block> =
-            ("else" _ eorb:expr_or_block(parser) { eorb })?
-
-        rule pattern(parser: &mut Parser) -> Pattern =
-            "(" _ variants:(pattern(parser) ++ ",") _ ")" { Pattern::TuplePattern(variants) } /
-            _ pat:simple_pattern(parser) { pat }
-
-        rule simple_pattern(parser: &mut Parser) -> Pattern =
-            pattern_literal() /
-            qn:qualified_identifier(parser) "(" members:(pattern(parser) ** ",") ")" {
-                Pattern::TupleStruct(qn, members)
-            } /
-            qn:qualified_identifier(parser) _ "{" _ items:(record_pattern_entry(parser) ** ",") "}" _ {
-                let items = items.into_iter().map(|(name, pat)| (Rc::new(name.to_string()), pat)).collect();
-                Pattern::Record(qn, items)
-            } /
-            qn:qualified_identifier(parser) { Pattern::VarOrName(qn) }
-
-        rule record_pattern_entry(parser: &mut Parser) -> (&'input str, Pattern) =
-            _ name:identifier() _ ":" _ pat:pattern(parser) _ { (name, pat) } /
-            _ name:identifier() _ {
-                let qn = QualifiedName {
-                    id: parser.fresh(),
-                    components: vec![Rc::new(name.to_string())],
-                };
-                (name, Pattern::VarOrName(qn))
-            }
-
-
-        rule pattern_literal() -> Pattern =
-            "true" { Pattern::Literal(PatternLiteral::BoolPattern(true)) } /
-            "false" { Pattern::Literal(PatternLiteral::BoolPattern(false)) } /
-            s:bare_string_literal() { Pattern::Literal(PatternLiteral::StringPattern(Rc::new(s))) } /
-            sign:("-"?)  num:(float_literal() / nat_literal()) {
-                let neg = sign.is_some();
-                Pattern::Literal(PatternLiteral::NumPattern { neg, num })
-            } /
-            "_" { Pattern::Ignored }
-
-
-        rule list_expr(parser: &mut Parser) -> ExpressionKind =
-            "[" exprs:(expression(parser) ** ",") "]" {
-                let mut exprs = exprs;
-                ExpressionKind::ListLiteral(exprs)
-            }
-
-        rule paren_expr(parser: &mut Parser) -> ExpressionKind =
-            "(" exprs:(expression(parser) ** ",") ")" {
-                let mut exprs = exprs;
-                match exprs.len() {
-                    1 => exprs.pop().unwrap().kind,
-                    _ => ExpressionKind::TupleLiteral(exprs),
-                }
-            }
-
-        rule string_literal() -> ExpressionKind =
-            prefix:identifier()? s:bare_string_literal(){ ExpressionKind::StringLiteral{ s: Rc::new(s),
-                prefix: prefix.map(rc_string)
-            } }
-
-        rule bare_string_literal() -> String =
-            "\"" chars:string_component()* "\"" { chars.into_iter().collect::<String>() }
-
-        rule string_component() -> char =
-            !(r#"""# / r#"\"#) ch:$([_]) { ch.chars().next().unwrap() } /
-            r#"\u{"# value:$(['0'..='9' | 'a'..='f' | 'A'..='F']+) "}" { char::from_u32(u32::from_str_radix(value, 16).unwrap()).unwrap() } /
-            r#"\n"# { '\n' } / r#"\t"# { '\t' } / r#"\""# { '"' } / r#"\\"# { '\\' } /
-      expected!("Valid escape sequence")
-
-        rule bool_literal() -> ExpressionKind =
-            "true" { ExpressionKind::BoolLiteral(true) } / "false" { ExpressionKind::BoolLiteral(false) }
-
-        rule nat_literal() -> ExpressionKind =
-            bin_literal() / hex_literal() / unmarked_literal()
-
-        rule unmarked_literal() -> ExpressionKind =
-            digits:digits() { let n = digits.chars().filter(|ch| *ch != '_').collect::<String>().parse().unwrap(); ExpressionKind::NatLiteral(n) }
-
-        rule bin_literal() -> ExpressionKind =
-            "0b" digits:bin_digits() {? parse_binary(digits).map(ExpressionKind::NatLiteral) }
-
-        rule hex_literal() -> ExpressionKind =
-            "0x" digits:hex_digits() {? parse_hex(digits).map(ExpressionKind::NatLiteral) }
-
-        rule float_literal() -> ExpressionKind =
-            ds:$( digits() "." digits()? / "." digits() ) { ExpressionKind::FloatLiteral(ds.parse().unwrap()) }
-
-        rule digits() -> &'input str = $((digit_group() "_"*)+)
-        rule bin_digits() -> &'input str = $((bin_digit_group() "_"*)+)
-        rule hex_digits() -> &'input str = $((hex_digit_group() "_"*)+)
-
-        rule digit_group() -> &'input str = $(['0'..='9']+)
-        rule bin_digit_group() -> &'input str = $(['0' | '1']+)
-        rule hex_digit_group() -> &'input str = $(['0'..='9' | 'a'..='f' | 'A'..='F']+)
-
-    }
-}
-
-fn parse_binary(digits: &str) -> Result<u64, &'static str> {
-    let mut result: u64 = 0;
-    let mut multiplier = 1;
-    for d in digits.chars().rev() {
-        match d {
-            '1' => result += multiplier,
-            '0' => (),
-            '_' => continue,
-            _ => unreachable!(),
-        }
-        multiplier = match multiplier.checked_mul(2) {
-            Some(m) => m,
-            None => return Err("Binary expression will overflow"),
-        }
-    }
-    Ok(result)
-}
-
-fn parse_hex(digits: &str) -> Result<u64, &'static str> {
-    let mut result: u64 = 0;
-    let mut multiplier: u64 = 1;
-    for d in digits.chars().rev() {
-        if d == '_' {
-            continue;
-        }
-        match d.to_digit(16) {
-            Some(n) => result += n as u64 * multiplier,
-            None => return Err("Internal parser error: invalid hex digit"),
-        }
-        multiplier = match multiplier.checked_mul(16) {
-            Some(m) => m,
-            None => return Err("Hexadecimal expression will overflow"),
-        }
-    }
-    Ok(result)
-}
-
-#[derive(Debug)]
-struct BinopSequence {
-    first: ExpressionKind,
-    next: Vec<(BinOp, ExpressionKind)>,
-}
-
-impl BinopSequence {
-    fn do_precedence(self, parser: &mut Parser) -> ExpressionKind {
-        fn helper(
-            precedence: i32,
-            lhs: ExpressionKind,
-            rest: &mut Vec<(BinOp, ExpressionKind)>,
-            parser: &mut Parser,
-        ) -> Expression {
-            let mut lhs = Expression::new(parser.fresh(), lhs);
-            while let Some((next_op, next_rhs)) = rest.pop() {
-                let new_precedence = next_op.get_precedence();
-                if precedence >= new_precedence {
-                    rest.push((next_op, next_rhs));
-                    break;
-                }
-                let rhs = helper(new_precedence, next_rhs, rest, parser);
-                lhs = Expression::new(
-                    parser.fresh(),
-                    ExpressionKind::BinExp(next_op, Box::new(lhs), Box::new(rhs)),
-                );
-            }
-            lhs
-        }
-        let mut as_stack = self.next.into_iter().rev().collect();
-        helper(BinOp::min_precedence(), self.first, &mut as_stack, parser).kind
-    }
-}

schala-lang/src/reduced_ir/mod.rs

@@ -1,484 +0,0 @@
-use std::{collections::HashMap, rc::Rc, str::FromStr};
-
-use crate::{
-    ast,
-    builtin::Builtin,
-    symbol_table::{DefId, SymbolSpec, SymbolTable},
-    type_inference::{TypeContext, TypeId},
-};
-
-mod test;
-mod types;
-
-pub use types::*;
-
-pub fn reduce(ast: &ast::AST, symbol_table: &SymbolTable, type_context: &TypeContext) -> ReducedIR {
-    let reducer = Reducer::new(symbol_table, type_context);
-    reducer.reduce(ast)
-}
-
-struct Reducer<'a, 'b> {
-    symbol_table: &'a SymbolTable,
-    functions: HashMap<DefId, FunctionDefinition>,
-    type_context: &'b TypeContext,
-}
-
-impl<'a, 'b> Reducer<'a, 'b> {
-    fn new(symbol_table: &'a SymbolTable, type_context: &'b TypeContext) -> Self {
-        Self { symbol_table, functions: HashMap::new(), type_context }
-    }
-
-    fn reduce(mut self, ast: &ast::AST) -> ReducedIR {
-        // First reduce all functions
-        // TODO once this works, maybe rewrite it using the Visitor
-        for statement in ast.statements.statements.iter() {
-            self.top_level_definition(statement);
-        }
-
-        // Then compute the entrypoint statements (which may reference previously-computed
-        // functions by ID)
-        let mut entrypoint = vec![];
-        for statement in ast.statements.statements.iter() {
-            let ast::Statement { id: item_id, kind, .. } = statement;
-            match &kind {
-                ast::StatementKind::Expression(expr) => {
-                    entrypoint.push(Statement::Expression(self.expression(expr)));
-                }
-                ast::StatementKind::Declaration(ast::Declaration::Binding {
-                    name: _,
-                    constant,
-                    expr,
-                    ..
-                }) => {
-                    let symbol = self.symbol_table.lookup_symbol(item_id).unwrap();
-                    entrypoint.push(Statement::Binding {
-                        id: symbol.def_id(),
-                        constant: *constant,
-                        expr: self.expression(expr),
-                    });
-                }
-                _ => (),
-            }
-        }
-
-        ReducedIR { functions: self.functions, entrypoint }
-    }
-
-    fn top_level_definition(&mut self, statement: &ast::Statement<ast::StatementKind>) {
-        let ast::Statement { id: item_id, kind, .. } = statement;
-        match kind {
-            ast::StatementKind::Expression(_expr) => {
-                //TODO expressions can in principle contain definitions, but I won't worry
-                //about it now
-            }
-            ast::StatementKind::Declaration(decl) => match decl {
-                ast::Declaration::FuncDecl(_, statements) => {
-                    self.insert_function_definition(item_id, statements);
-                }
-                ast::Declaration::Impl { type_name: _, interface_name: _, block } =>
-                    for item in block {
-                        if let ast::Statement {
-                            id: item_id,
-                            kind: ast::Declaration::FuncDecl(_, statements),
-                            ..
-                        } = item
-                        {
-                            self.insert_function_definition(item_id, statements);
-                        }
-                    },
-                _ => (),
-            },
-            // Imports should have already been processed by the symbol table and are irrelevant
-            // for this representation.
-            ast::StatementKind::Import(..) => (),
-            ast::StatementKind::Flow(..) => {
-                //TODO this should be an error
-            }
-        }
-    }
-
-    fn function_internal_statement(
-        &mut self,
-        statement: &ast::Statement<ast::StatementKind>,
-    ) -> Option<Statement> {
-        let ast::Statement { id: item_id, kind, .. } = statement;
-        match kind {
-            ast::StatementKind::Expression(expr) => Some(Statement::Expression(self.expression(expr))),
-            ast::StatementKind::Declaration(decl) => match decl {
-                ast::Declaration::FuncDecl(_, statements) => {
-                    self.insert_function_definition(item_id, statements);
-                    None
-                }
-                ast::Declaration::Binding { constant, expr, .. } => {
-                    let symbol = self.symbol_table.lookup_symbol(item_id).unwrap();
-                    Some(Statement::Binding {
-                        id: symbol.def_id(),
-                        constant: *constant,
-                        expr: self.expression(expr),
-                    })
-                }
-                _ => None,
-            },
-            ast::StatementKind::Import(_) => None,
-            ast::StatementKind::Flow(ast::FlowControl::Return(expr)) =>
-                if let Some(expr) = expr {
-                    Some(Statement::Return(self.expression(expr)))
-                } else {
-                    Some(Statement::Return(Expression::unit()))
-                },
-            ast::StatementKind::Flow(ast::FlowControl::Break) => Some(Statement::Break),
-            ast::StatementKind::Flow(ast::FlowControl::Continue) => Some(Statement::Continue),
-        }
-    }
-
-    fn insert_function_definition(&mut self, item_id: &ast::ItemId, statements: &ast::Block) {
-        let symbol = self.symbol_table.lookup_symbol(item_id).unwrap();
-        let function_def = FunctionDefinition { body: self.function_internal_block(statements) };
-        self.functions.insert(symbol.def_id(), function_def);
-    }
-
-    //TODO this needs to be type-aware to work correctly
-    fn lookup_method(&mut self, name: &str) -> Option<DefId> {
-        for (def_id, function) in self.functions.iter() {
-            let symbol = self.symbol_table.lookup_symbol_by_def(def_id)?;
-            println!("Def Id: {} symbol: {:?}", def_id, symbol);
-            if symbol.local_name() == name {
-                return Some(*def_id);
-            }
-        }
-        None
-    }
-
-    fn expression(&mut self, expr: &ast::Expression) -> Expression {
-        use crate::ast::ExpressionKind::*;
-
-        match &expr.kind {
-            SelfValue => Expression::Lookup(Lookup::SelfParam),
-            NatLiteral(n) => Expression::Literal(Literal::Nat(*n)),
-            FloatLiteral(f) => Expression::Literal(Literal::Float(*f)),
-            //TODO implement handling string literal prefixes
-            StringLiteral { s, prefix: _ } => Expression::Literal(Literal::StringLit(s.clone())),
-            BoolLiteral(b) => Expression::Literal(Literal::Bool(*b)),
-            BinExp(binop, lhs, rhs) => self.binop(binop, lhs, rhs),
-            PrefixExp(op, arg) => self.prefix(op, arg),
-            Value(qualified_name) => self.value(qualified_name),
-            Call { f, arguments } => {
-                let f = self.expression(f);
-                let args = arguments.iter().map(|arg| self.invocation_argument(arg)).collect();
-                //TODO need to have full type availability at this point to do this method lookup
-                //correctly
-                if let Expression::Access { name, expr } = f {
-                    let def_id = self.lookup_method(&name).unwrap();
-                    let method = Expression::Lookup(Lookup::Function(def_id));
-                    Expression::CallMethod { f: Box::new(method), args, self_expr: expr }
-                } else {
-                    Expression::Call { f: Box::new(f), args }
-                }
-            }
-            TupleLiteral(exprs) => Expression::Tuple(exprs.iter().map(|e| self.expression(e)).collect()),
-            IfExpression { discriminator, body } =>
-                self.reduce_if_expression(discriminator.as_ref().map(|x| x.as_ref()), body),
-            Lambda { params, body, .. } => Expression::Callable(Callable::Lambda {
-                arity: params.len() as u8,
-                body: self.function_internal_block(body),
-            }),
-            NamedStruct { name, fields } => {
-                let symbol = match self.symbol_table.lookup_symbol(&name.id) {
-                    Some(symbol) => symbol,
-                    None => return Expression::ReductionError(format!("No symbol found for {}", name)),
-                };
-                let (tag, type_id) = match symbol.spec() {
-                    SymbolSpec::RecordConstructor { tag, type_id } => (tag, type_id),
-                    e => return Expression::ReductionError(format!("Bad symbol for NamedStruct: {:?}", e)),
-                };
-
-                let field_order = compute_field_orderings(self.type_context, &type_id, tag).unwrap();
-
-                let mut field_map = HashMap::new();
-                for (name, expr) in fields.iter() {
-                    field_map.insert(name.as_ref(), expr);
-                }
-
-                let mut ordered_args = vec![];
-                for field in field_order.iter() {
-                    let expr = match field_map.get(&field) {
-                        Some(expr) => expr,
-                        None =>
-                            return Expression::ReductionError(format!(
-                                "Field {} not specified for record {}",
-                                field, name
-                            )),
-                    };
-                    ordered_args.push(self.expression(expr));
-                }
-
-                let constructor =
-                    Expression::Callable(Callable::RecordConstructor { type_id, tag, field_order });
-                Expression::Call { f: Box::new(constructor), args: ordered_args }
-            }
-            Index { indexee, indexers } => self.reduce_index(indexee.as_ref(), indexers.as_slice()),
-            WhileExpression { condition, body } => {
-                let cond = Box::new(if let Some(condition) = condition {
-                    self.expression(condition)
-                } else {
-                    Expression::Literal(Literal::Bool(true))
-                });
-                let statements = self.function_internal_block(body);
-                Expression::Loop { cond, statements }
-            }
-            ForExpression { .. } => Expression::ReductionError("For expr not implemented".to_string()),
-            ListLiteral(items) => Expression::List(items.iter().map(|item| self.expression(item)).collect()),
-            Access { name, expr } =>
-                Expression::Access { name: name.as_ref().to_string(), expr: Box::new(self.expression(expr)) },
-        }
-    }
-
-    //TODO figure out the semantics of multiple indexers - for now, just ignore them
-    fn reduce_index(&mut self, indexee: &ast::Expression, indexers: &[ast::Expression]) -> Expression {
-        if indexers.len() != 1 {
-            return Expression::ReductionError("Invalid index expression".to_string());
-        }
-        let indexee = self.expression(indexee);
-        let indexer = self.expression(&indexers[0]);
-        Expression::Index { indexee: Box::new(indexee), indexer: Box::new(indexer) }
-    }
-
-    fn reduce_if_expression(
-        &mut self,
-        discriminator: Option<&ast::Expression>,
-        body: &ast::IfExpressionBody,
-    ) -> Expression {
-        use ast::IfExpressionBody::*;
-
-        let cond = Box::new(match discriminator {
-            Some(expr) => self.expression(expr),
-            None => return Expression::ReductionError("blank cond if-expr not supported".to_string()),
-        });
-        match body {
-            SimpleConditional { then_case, else_case } => {
-                let then_clause = self.function_internal_block(then_case);
-                let else_clause = match else_case.as_ref() {
-                    None => vec![],
-                    Some(stmts) => self.function_internal_block(stmts),
-                };
-                Expression::Conditional { cond, then_clause, else_clause }
-            }
-            SimplePatternMatch { pattern, then_case, else_case } => {
-                let alternatives = vec![
-                    Alternative {
-                        pattern: match pattern.reduce(self.symbol_table) {
-                            Ok(p) => p,
-                            Err(e) => return Expression::ReductionError(format!("Bad pattern: {:?}", e)),
-                        },
-                        item: self.function_internal_block(then_case),
-                    },
-                    Alternative {
-                        pattern: Pattern::Ignored,
-                        item: match else_case.as_ref() {
-                            Some(else_case) => self.function_internal_block(else_case),
-                            None => vec![],
-                        },
-                    },
-                ];
-
-                Expression::CaseMatch { cond, alternatives }
-            }
-            CondList(ref condition_arms) => {
-                let mut alternatives = vec![];
-                for arm in condition_arms {
-                    match arm.condition {
-                        ast::Condition::Pattern(ref pat) => {
-                            let alt = Alternative {
-                                pattern: match pat.reduce(self.symbol_table) {
-                                    Ok(p) => p,
-                                    Err(e) =>
-                                        return Expression::ReductionError(format!("Bad pattern: {:?}", e)),
-                                },
-                                item: self.function_internal_block(&arm.body),
-                            };
-                            alternatives.push(alt);
-                        }
-                        ast::Condition::TruncatedOp(_, _) =>
-                            return Expression::ReductionError("case-expression-trunc-op".to_string()),
-                        ast::Condition::Else =>
-                            return Expression::ReductionError("case-expression-else".to_string()),
-                    }
-                }
-                Expression::CaseMatch { cond, alternatives }
-            }
-        }
-    }
-
-    fn invocation_argument(&mut self, invoc: &ast::InvocationArgument) -> Expression {
-        use crate::ast::InvocationArgument::*;
-        match invoc {
-            Positional(ex) => self.expression(ex),
-            Keyword { .. } => Expression::ReductionError("Keyword arguments not supported".to_string()),
-            Ignored => Expression::ReductionError("Ignored arguments not supported".to_string()),
-        }
-    }
-
-    fn function_internal_block(&mut self, block: &ast::Block) -> Vec<Statement> {
-        block.statements.iter().filter_map(|stmt| self.function_internal_statement(stmt)).collect()
-    }
-
-    fn prefix(&mut self, prefix: &ast::PrefixOp, arg: &ast::Expression) -> Expression {
-        let builtin: Option<Builtin> = TryFrom::try_from(prefix).ok();
-        match builtin {
-            Some(op) => Expression::Call {
-                f: Box::new(Expression::Callable(Callable::Builtin(op))),
-                args: vec![self.expression(arg)],
-            },
-            None => {
-                //TODO need this for custom prefix ops
-                Expression::ReductionError("User-defined prefix ops not supported".to_string())
-            }
-        }
-    }
-
-    fn binop(&mut self, binop: &ast::BinOp, lhs: &ast::Expression, rhs: &ast::Expression) -> Expression {
-        use Expression::ReductionError;
-
-        let operation = Builtin::from_str(binop.sigil()).ok();
-        match operation {
-            Some(Builtin::Assignment) => {
-                let lval = match &lhs.kind {
-                    ast::ExpressionKind::Value(qualified_name) => {
-                        if let Some(symbol) = self.symbol_table.lookup_symbol(&qualified_name.id) {
-                            symbol.def_id()
-                        } else {
-                            return ReductionError(format!("Couldn't look up name: {:?}", qualified_name));
-                        }
-                    }
-                    _ => return ReductionError("Trying to assign to a non-name".to_string()),
-                };
-
-                Expression::Assign { lval, rval: Box::new(self.expression(rhs)) }
-            }
-            Some(op) => Expression::Call {
-                f: Box::new(Expression::Callable(Callable::Builtin(op))),
-                args: vec![self.expression(lhs), self.expression(rhs)],
-            },
-            //TODO handle a user-defined operation
-            None => ReductionError("User-defined operations not supported".to_string()),
-        }
-    }
-
-    fn value(&mut self, qualified_name: &ast::QualifiedName) -> Expression {
-        use SymbolSpec::*;
-
-        let symbol = match self.symbol_table.lookup_symbol(&qualified_name.id) {
-            Some(s) => s,
-            None =>
-                return Expression::ReductionError(format!("No symbol found for name: `{}`", qualified_name)),
-        };
-
-        let def_id = symbol.def_id();
-
-        match symbol.spec() {
-            Builtin(b) => Expression::Callable(Callable::Builtin(b)),
-            Func { .. } => Expression::Lookup(Lookup::Function(def_id)),
-            GlobalBinding => Expression::Lookup(Lookup::GlobalVar(def_id)),
-            LocalVariable => Expression::Lookup(Lookup::LocalVar(def_id)),
-            FunctionParam(n) => Expression::Lookup(Lookup::Param(n)),
-            DataConstructor { tag, type_id } =>
-                Expression::Callable(Callable::DataConstructor { type_id, tag }),
-            RecordConstructor { .. } => Expression::ReductionError(format!(
-                "The symbol for value {:?} is unexpectdly a RecordConstructor",
-                qualified_name
-            )),
-        }
-    }
-}
-
-impl ast::Pattern {
-    fn reduce(&self, symbol_table: &SymbolTable) -> Result<Pattern, PatternError> {
-        Ok(match self {
-            ast::Pattern::Ignored => Pattern::Ignored,
-            ast::Pattern::TuplePattern(subpatterns) => {
-                let items: Result<Vec<Pattern>, PatternError> =
-                    subpatterns.iter().map(|pat| pat.reduce(symbol_table)).into_iter().collect();
-                let items = items?;
-                Pattern::Tuple { tag: None, subpatterns: items }
-            }
-            ast::Pattern::Literal(lit) => Pattern::Literal(match lit {
-                ast::PatternLiteral::NumPattern { neg, num } => match (neg, num) {
-                    (false, ast::ExpressionKind::NatLiteral(n)) => Literal::Nat(*n),
-                    (false, ast::ExpressionKind::FloatLiteral(f)) => Literal::Float(*f),
-                    (true, ast::ExpressionKind::NatLiteral(n)) => Literal::Int(-(*n as i64)),
-                    (true, ast::ExpressionKind::FloatLiteral(f)) => Literal::Float(-f),
-                    (_, e) =>
-                        return Err(format!("Internal error, unexpected pattern literal: {:?}", e).into()),
-                },
-                ast::PatternLiteral::StringPattern(s) => Literal::StringLit(s.clone()),
-                ast::PatternLiteral::BoolPattern(b) => Literal::Bool(*b),
-            }),
-            ast::Pattern::TupleStruct(name, subpatterns) => {
-                let symbol = symbol_table.lookup_symbol(&name.id).unwrap();
-                if let SymbolSpec::DataConstructor { tag, type_id: _ } = symbol.spec() {
-                    let items: Result<Vec<Pattern>, PatternError> =
-                        subpatterns.iter().map(|pat| pat.reduce(symbol_table)).into_iter().collect();
-                    let items = items?;
-                    Pattern::Tuple { tag: Some(tag), subpatterns: items }
-                } else {
-                    return Err(
-                        "Internal error, trying to match something that's not a DataConstructor".into()
-                    );
-                }
-            }
-            ast::Pattern::VarOrName(name) => {
-                let symbol = symbol_table.lookup_symbol(&name.id).unwrap();
-                match symbol.spec() {
-                    SymbolSpec::DataConstructor { tag, type_id: _ } =>
-                        Pattern::Tuple { tag: Some(tag), subpatterns: vec![] },
-                    SymbolSpec::LocalVariable => {
-                        let def_id = symbol.def_id();
-                        Pattern::Binding(def_id)
-                    }
-                    spec => return Err(format!("Unexpected VarOrName symbol: {:?}", spec).into()),
-                }
-            }
-            ast::Pattern::Record(name, specified_members) => {
-                let symbol = symbol_table.lookup_symbol(&name.id).unwrap();
-                if let SymbolSpec::RecordConstructor { tag, type_id: _ } = symbol.spec() {
-                    //TODO do this computation from the type_id
-                    /*
-                    if specified_members.iter().any(|(member, _)| !members.contains_key(member)) {
-                        return Err(format!("Unknown key in record pattern").into());
-                    }
-                    */
-
-                    let subpatterns: Result<Vec<(Rc<String>, Pattern)>, PatternError> = specified_members
-                        .iter()
-                        .map(|(name, pat)| {
-                            pat.reduce(symbol_table).map(|reduced_pat| (name.clone(), reduced_pat))
-                        })
-                        .into_iter()
-                        .collect();
-                    let subpatterns = subpatterns?;
-                    Pattern::Record { tag, subpatterns }
-                } else {
-                    return Err(format!("Unexpected Record pattern symbol: {:?}", symbol.spec()).into());
-                }
-            }
-        })
-    }
-}
-
-/// Given the type context and a variant, compute what order the fields on it were stored.
-/// This needs to be public until type-checking is fully implemented because the type information
-/// is only available at runtime.
-pub fn compute_field_orderings(
-    type_context: &TypeContext,
-    type_id: &TypeId,
-    tag: u32,
-) -> Option<Vec<String>> {
-    // Eventually, the ReducedIR should decide what field ordering is optimal.
-    // For now, just do it alphabetically.
-
-    let record_members = type_context.lookup_record_members(type_id, tag)?;
-    let mut field_order: Vec<String> =
-        record_members.iter().map(|(field, _type_id)| field).cloned().collect();
-    field_order.sort_unstable();
-    Some(field_order)
-}

schala-lang/src/reduced_ir/test.rs

@@ -1,61 +0,0 @@
-#![cfg(test)]
-
-use super::*;
-use crate::{symbol_table::SymbolTable, type_inference::TypeContext};
-
-fn build_ir(input: &str) -> ReducedIR {
-    let ast = crate::util::quick_ast(input);
-
-    let mut symbol_table = SymbolTable::new();
-    let mut type_context = TypeContext::new();
-
-    symbol_table.process_ast(&ast, &mut type_context).unwrap();
-
-    let reduced = reduce(&ast, &symbol_table, &type_context);
-    reduced.debug(&symbol_table);
-    reduced
-}
-
-#[test]
-fn test_ir() {
-    let src = r#"
-
-    let global_one = 10 + 20
-    let global_two = "the string hello"
-
-    fn a_function(i, j, k) {
-        fn nested(x) {
-            x + 10
-        }
-        i + j * nested(k)
-    }
-
-    fn another_function(e) {
-        let local_var = 420
-        e * local_var
-    }
-
-    another_function()
-    "#;
-
-    let reduced = build_ir(src);
-    assert_eq!(reduced.functions.len(), 3);
-}
-
-#[test]
-fn test_methods() {
-    let src = r#"
-type Thing = Thing
-impl Thing {
-    fn a_method() {
-        20
-    }
-
-}
-
-let a = Thing
-4 + a.a_method()
-    "#;
-    let reduced = build_ir(src);
-    assert_eq!(reduced.functions.len(), 1);
-}

schala-lang/src/reduced_ir/types.rs

@@ -1,137 +0,0 @@
-use std::{collections::HashMap, convert::From, rc::Rc};
-
-use crate::{
-    builtin::Builtin,
-    symbol_table::{DefId, SymbolTable},
-    type_inference::TypeId,
-};
-
-//TODO most of these Clone impls only exist to support function application, because the
-//tree-walking evaluator moves the reduced IR members.
-
-/// The reduced intermediate representation consists of a list of function definitions, and a block
-/// of entrypoint statements.  In a repl or script context this can be an arbitrary list of
-/// statements, in an executable context will likely just be a pointer to the main() function.
-#[derive(Debug)]
-pub struct ReducedIR {
-    pub functions: HashMap<DefId, FunctionDefinition>,
-    pub entrypoint: Vec<Statement>,
-}
-
-impl ReducedIR {
-    #[allow(dead_code)]
-    pub fn debug(&self, symbol_table: &SymbolTable) {
-        println!("Reduced IR:");
-        println!("Functions:");
-        println!("-----------");
-        for (id, callable) in self.functions.iter() {
-            let name = &symbol_table.lookup_symbol_by_def(id).unwrap().local_name();
-            println!("{}({}) -> {:?}", id, name, callable);
-        }
-        println!();
-        println!("Entrypoint:");
-        println!("-----------");
-        for stmt in self.entrypoint.iter() {
-            println!("{:?}", stmt);
-        }
-        println!("-----------");
-    }
-}
-
-#[derive(Debug, Clone)]
-pub enum Statement {
-    Expression(Expression),
-    Binding { id: DefId, constant: bool, expr: Expression },
-    Return(Expression),
-    Continue,
-    Break,
-}
-
-#[derive(Debug, Clone)]
-pub enum Expression {
-    Literal(Literal),
-    Tuple(Vec<Expression>),
-    List(Vec<Expression>),
-    Lookup(Lookup),
-    Assign { lval: DefId, rval: Box<Expression> },
-    Access { name: String, expr: Box<Expression> },
-    Callable(Callable),
-    Call { f: Box<Expression>, args: Vec<Expression> },
-    CallMethod { f: Box<Expression>, args: Vec<Expression>, self_expr: Box<Expression> },
-    Conditional { cond: Box<Expression>, then_clause: Vec<Statement>, else_clause: Vec<Statement> },
-    CaseMatch { cond: Box<Expression>, alternatives: Vec<Alternative> },
-    Loop { cond: Box<Expression>, statements: Vec<Statement> },
-    Index { indexee: Box<Expression>, indexer: Box<Expression> },
-    ReductionError(String),
-}
-
-impl Expression {
-    pub fn unit() -> Self {
-        Expression::Tuple(vec![])
-    }
-}
-
-#[derive(Debug)]
-pub struct FunctionDefinition {
-    pub body: Vec<Statement>,
-}
-
-#[derive(Debug, Clone)]
-pub enum Callable {
-    Builtin(Builtin),
-    UserDefined(DefId),
-    Lambda { arity: u8, body: Vec<Statement> },
-    DataConstructor { type_id: TypeId, tag: u32 },
-    RecordConstructor { type_id: TypeId, tag: u32, field_order: Vec<String> },
-}
-
-#[derive(Debug, Clone)]
-pub enum Lookup {
-    LocalVar(DefId),
-    GlobalVar(DefId),
-    Function(DefId),
-    Param(u8),
-    SelfParam,
-}
-
-#[derive(Debug, Clone, PartialEq)]
-pub enum Literal {
-    Nat(u64),
-    Int(i64),
-    Float(f64),
-    Bool(bool),
-    StringLit(Rc<String>),
-}
-
-#[derive(Debug, Clone)]
-pub struct Alternative {
-    pub pattern: Pattern,
-    pub item: Vec<Statement>,
-}
-
-#[derive(Debug, Clone)]
-pub enum Pattern {
-    Tuple { subpatterns: Vec<Pattern>, tag: Option<u32> },
-    Record { tag: u32, subpatterns: Vec<(Rc<String>, Pattern)> },
-    Literal(Literal),
-    Ignored,
-    Binding(DefId),
-}
-
-#[allow(dead_code)]
-#[derive(Debug)]
-pub struct PatternError {
-    msg: String,
-}
-
-impl From<&str> for PatternError {
-    fn from(s: &str) -> Self {
-        Self { msg: s.to_string() }
-    }
-}
-
-impl From<String> for PatternError {
-    fn from(msg: String) -> Self {
-        Self { msg }
-    }
-}

schala-lang/src/schala.rs

@@ -1,210 +0,0 @@
-use schala_repl::{
-    ComputationRequest, ComputationResponse, GlobalOutputStats, LangMetaRequest, LangMetaResponse,
-    ProgrammingLanguageInterface,
-};
-use stopwatch::Stopwatch;
-
-use crate::{error::SchalaError, parsing, reduced_ir, symbol_table, tree_walk_eval, type_inference};
-
-/// All the state necessary to parse and execute a Schala program are stored in this struct.
-pub struct Schala<'a> {
-    /// Holds a reference to the original source code, parsed into line and character
-    source_reference: SourceReference,
-
-    //state: eval::State<'static>,
-    /// Keeps track of symbols and scopes
-    symbol_table: symbol_table::SymbolTable,
-    /// Contains information for type-checking
-    type_context: type_inference::TypeContext,
-    /// Schala Parser
-    active_parser: parsing::Parser,
-
-    /// Execution state for AST-walking interpreter
-    eval_state: tree_walk_eval::State<'a>,
-
-    timings: Vec<(&'static str, std::time::Duration)>,
-}
-
-/*
-impl Schala {
-    //TODO implement documentation for language items
-    /*
-    fn handle_docs(&self, source: String) -> LangMetaResponse {
-      LangMetaResponse::Docs {
-        doc_string: format!("Schala item `{}` : <<Schala-lang documentation not yet implemented>>", source)
-      }
-    }
-    */
-}
-*/
-
-impl<'a> Schala<'a> {
-    /// Creates a new Schala environment *without* any prelude.
-    fn new_blank_env() -> Schala<'a> {
-        Schala {
-            source_reference: SourceReference::new(),
-            symbol_table: symbol_table::SymbolTable::new(),
-            type_context: type_inference::TypeContext::new(),
-            active_parser: parsing::Parser::new(),
-            eval_state: tree_walk_eval::State::new(),
-            timings: Vec::new(),
-        }
-    }
-
-    /// Creates a new Schala environment with the standard prelude, which is defined as ordinary
-    /// Schala code in the file `prelude.schala`
-    #[allow(clippy::new_without_default)]
-    pub fn new() -> Schala<'a> {
-        let prelude = include_str!("../source-files/prelude.schala");
-        let mut env = Schala::new_blank_env();
-
-        let response = env.run_pipeline(prelude, SchalaConfig::default());
-        if let Err(err) = response {
-            panic!("Error in prelude, panicking: {}", err.display());
-        }
-        env
-    }
-
-    /// This is where the actual action of interpreting/compilation happens.
-    /// Note: this should eventually use a query-based system for parallelization, cf.
-    /// https://rustc-dev-guide.rust-lang.org/overview.html
-    fn run_pipeline(&mut self, source: &str, config: SchalaConfig) -> Result<String, SchalaError> {
-        self.timings = vec![];
-        let sw = Stopwatch::start_new();
-
-        self.source_reference.load_new_source(source);
-        let ast = self
-            .active_parser
-            .parse(source)
-            .map_err(|err| SchalaError::from_parse_error(err, &self.source_reference))?;
-        self.timings.push(("parsing", sw.elapsed()));
-
-        let sw = Stopwatch::start_new();
-        //Perform all symbol table work
-        self.symbol_table
-            .process_ast(&ast, &mut self.type_context)
-            .map_err(SchalaError::from_symbol_table)?;
-
-        self.timings.push(("symbol_table", sw.elapsed()));
-
-        // Typechecking
-        let _overall_type = self.type_context.typecheck(&ast).map_err(SchalaError::from_type_error);
-
-        let sw = Stopwatch::start_new();
-        let reduced_ir = reduced_ir::reduce(&ast, &self.symbol_table, &self.type_context);
-        self.timings.push(("reduced_ir", sw.elapsed()));
-
-        let sw = Stopwatch::start_new();
-        let evaluation_outputs = self.eval_state.evaluate(reduced_ir, &self.type_context, config.repl);
-        self.timings.push(("tree-walking-evaluation", sw.elapsed()));
-        let text_output: Result<Vec<String>, String> = evaluation_outputs.into_iter().collect();
-
-        let text_output: Result<Vec<String>, SchalaError> =
-            text_output.map_err(|err| SchalaError::from_string(err, Stage::Evaluation));
-
-        let eval_output: String =
-            text_output.map(|v| Iterator::intersperse(v.into_iter(), "\n".to_owned()).collect())?;
-
-        Ok(eval_output)
-    }
-}
-
-/// Represents lines of source code
-pub(crate) struct SourceReference {
-    last_source: Option<String>,
-    /// Offsets in *bytes* (not chars) representing a newline character
-    newline_offsets: Vec<usize>,
-}
-
-impl SourceReference {
-    pub(crate) fn new() -> SourceReference {
-        SourceReference { last_source: None, newline_offsets: vec![] }
-    }
-
-    pub(crate) fn load_new_source(&mut self, source: &str) {
-        self.newline_offsets = vec![];
-        for (offset, ch) in source.as_bytes().iter().enumerate() {
-            if *ch == b'\n' {
-                self.newline_offsets.push(offset);
-            }
-        }
-        self.last_source = Some(source.to_string());
-    }
-
-    // (line_start, line_num, the string itself)
-    pub fn get_line(&self, line: usize) -> (usize, usize, String) {
-        if self.newline_offsets.is_empty() {
-            return (0, 0, self.last_source.as_ref().cloned().unwrap());
-        }
-
-        //TODO make sure this is utf8-safe
-        let start_idx = match self.newline_offsets.binary_search(&line) {
-            Ok(index) | Err(index) => index,
-        };
-
-        let last_source = self.last_source.as_ref().unwrap();
-
-        let start = self.newline_offsets[start_idx];
-        let end = self.newline_offsets.get(start_idx + 1).cloned().unwrap_or_else(|| last_source.len());
-
-        let slice = &last_source.as_bytes()[start..end];
-        (start, start_idx, std::str::from_utf8(slice).unwrap().to_string())
-    }
-}
-
-#[allow(dead_code)]
-#[derive(Clone, Copy, Debug)]
-pub(crate) enum Stage {
-    Parsing,
-    Symbols,
-    ScopeResolution,
-    Typechecking,
-    AstReduction,
-    Evaluation,
-}
-
-fn stage_names() -> Vec<&'static str> {
-    vec!["parsing", "symbol-table", "typechecking", "ast-reduction", "ast-walking-evaluation"]
-}
-
-#[derive(Default, Clone)]
-pub struct SchalaConfig {
-    pub repl: bool,
-}
-
-impl<'a> ProgrammingLanguageInterface for Schala<'a> {
-    //TODO flesh out Config
-    type Config = SchalaConfig;
-    fn language_name() -> String {
-        "Schala".to_owned()
-    }
-
-    fn source_file_suffix() -> String {
-        "schala".to_owned()
-    }
-
-    fn run_computation(&mut self, request: ComputationRequest<Self::Config>) -> ComputationResponse {
-        let ComputationRequest { source, debug_requests: _, config: _ } = request;
-        let sw = Stopwatch::start_new();
-
-        let main_output =
-            self.run_pipeline(source, request.config).map_err(|schala_err| schala_err.display());
-        let total_duration = sw.elapsed();
-
-        let stage_durations: Vec<_> = std::mem::take(&mut self.timings)
-            .into_iter()
-            .map(|(label, duration)| (label.to_string(), duration))
-            .collect();
-        let global_output_stats = GlobalOutputStats { total_duration, stage_durations };
-
-        ComputationResponse { main_output, global_output_stats, debug_responses: vec![] }
-    }
-
-    fn request_meta(&mut self, request: LangMetaRequest) -> LangMetaResponse {
-        match request {
-            LangMetaRequest::StageNames =>
-                LangMetaResponse::StageNames(stage_names().iter().map(|s| s.to_string()).collect()),
-            _ => LangMetaResponse::Custom { kind: "not-implemented".to_string(), value: "".to_string() },
-        }
-    }
-}

schala-lang/src/symbol_table/fqsn.rs

@@ -1,65 +0,0 @@
-use std::{fmt, rc::Rc};
-
-/// Fully-qualified symbol name
-#[derive(Debug, Clone, Eq, PartialEq, Hash, PartialOrd, Ord)]
-pub struct Fqsn {
-    //TODO Fqsn's need to be cheaply cloneable
-    pub scopes: Vec<ScopeSegment>,
-}
-
-impl Fqsn {
-    pub fn from_scope_stack(scopes: &[ScopeSegment], new_name: Rc<String>) -> Self {
-        let mut v = Vec::new();
-        for s in scopes {
-            v.push(s.clone());
-        }
-        v.push(ScopeSegment::Name(new_name));
-        Fqsn { scopes: v }
-    }
-
-    pub fn extend(&self, new_item: &str) -> Self {
-        let mut new = self.clone();
-        new.scopes.push(ScopeSegment::Name(Rc::new(new_item.to_string())));
-        new
-    }
-
-    #[allow(dead_code)]
-    pub fn from_strs(strs: &[&str]) -> Fqsn {
-        let mut scopes = vec![];
-        for s in strs {
-            scopes.push(ScopeSegment::Name(Rc::new(s.to_string())));
-        }
-        Fqsn { scopes }
-    }
-
-    pub fn last_elem(&self) -> Rc<String> {
-        let ScopeSegment::Name(name) = self.scopes.last().unwrap();
-        name.clone()
-    }
-}
-
-impl fmt::Display for Fqsn {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        let delim = "::";
-        let Fqsn { scopes } = self;
-        write!(f, "FQSN<{}", scopes[0])?;
-        for item in scopes[1..].iter() {
-            write!(f, "{}{}", delim, item)?;
-        }
-        write!(f, ">")
-    }
-}
-
-//TODO eventually this should use ItemId's to avoid String-cloning
-/// One segment within a scope.
-#[derive(Debug, Clone, Eq, PartialEq, Hash, PartialOrd, Ord)]
-pub enum ScopeSegment {
-    Name(Rc<String>),
-}
-
-impl fmt::Display for ScopeSegment {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        let ScopeSegment::Name(name) = self;
-        write!(f, "{}", name)
-    }
-}

schala-lang/src/symbol_table/mod.rs

@@ -1,244 +0,0 @@
-#![allow(clippy::enum_variant_names)]
-
-use std::{
-    collections::{hash_map::Entry, HashMap},
-    fmt,
-    rc::Rc,
-};
-
-use crate::{
-    ast,
-    ast::ItemId,
-    builtin::Builtin,
-    parsing::Location,
-    type_inference::{TypeContext, TypeId},
-};
-
-mod populator;
-use populator::SymbolTablePopulator;
-mod fqsn;
-pub use fqsn::{Fqsn, ScopeSegment};
-mod resolver;
-mod symbol_trie;
-use symbol_trie::SymbolTrie;
-mod test;
-use crate::identifier::{define_id_kind, Id, IdStore};
-
-define_id_kind!(DefItem);
-pub type DefId = Id<DefItem>;
-
-#[allow(dead_code)]
-#[derive(Debug, Clone)]
-pub enum SymbolError {
-    DuplicateName { prev_name: Fqsn, location: Location },
-    DuplicateVariant { type_fqsn: Fqsn, name: String },
-    DuplicateRecord { type_fqsn: Fqsn, location: Location, record: String, member: String },
-    UnknownAnnotation { name: String },
-    BadAnnotation { name: String, msg: String },
-    BadImplBlockEntry,
-}
-
-#[allow(dead_code)]
-#[derive(Debug)]
-struct NameSpec<K> {
-    location: Location,
-    kind: K,
-}
-
-#[derive(Debug)]
-enum NameKind {
-    Module,
-    Function,
-    Binding,
-}
-
-#[derive(Debug)]
-enum TypeKind {
-    Function,
-    Constructor,
-}
-
-/// Keeps track of what names were used in a given namespace.
-struct NameTable<K> {
-    table: HashMap<Fqsn, NameSpec<K>>,
-}
-
-impl<K> NameTable<K> {
-    fn new() -> Self {
-        Self { table: HashMap::new() }
-    }
-
-    fn register(&mut self, name: Fqsn, spec: NameSpec<K>) -> Result<(), SymbolError> {
-        match self.table.entry(name.clone()) {
-            Entry::Occupied(o) =>
-                Err(SymbolError::DuplicateName { prev_name: name, location: o.get().location }),
-            Entry::Vacant(v) => {
-                v.insert(spec);
-                Ok(())
-            }
-        }
-    }
-}
-
-//cf. p. 150 or so of Language Implementation Patterns
-pub struct SymbolTable {
-    def_id_store: IdStore<DefItem>,
-
-    /// Used for import resolution.
-    symbol_trie: SymbolTrie,
-
-    /// These tables are responsible for preventing duplicate names.
-    fq_names: NameTable<NameKind>, //Note that presence of two tables implies that a type and other binding with the same name can co-exist
-    types: NameTable<TypeKind>,
-
-    id_to_def: HashMap<ItemId, DefId>,
-    def_to_symbol: HashMap<DefId, Rc<Symbol>>,
-}
-
-impl SymbolTable {
-    /// Create a new, empty SymbolTable
-    pub fn new() -> Self {
-        Self {
-            def_id_store: IdStore::new(),
-            symbol_trie: SymbolTrie::new(),
-            fq_names: NameTable::new(),
-            types: NameTable::new(),
-            id_to_def: HashMap::new(),
-            def_to_symbol: HashMap::new(),
-        }
-    }
-
-    /// The main entry point into the symbol table. This will traverse the AST in several
-    /// different ways and populate subtables with information that will be used further in the
-    /// compilation process.
-    pub fn process_ast(
-        &mut self,
-        ast: &ast::AST,
-        type_context: &mut TypeContext,
-    ) -> Result<(), Vec<SymbolError>> {
-        let mut populator = SymbolTablePopulator { type_context, table: self };
-
-        let errs = populator.populate_definition_tables(ast);
-        if !errs.is_empty() {
-            return Err(errs);
-        }
-
-        // Walks the AST, matching the ID of an identifier used in some expression to
-        // the corresponding Symbol.
-        let mut resolver = resolver::ScopeResolver::new(self);
-        resolver.resolve(ast);
-
-        Ok(())
-    }
-
-    pub fn lookup_symbol(&self, id: &ItemId) -> Option<&Symbol> {
-        let def = self.id_to_def.get(id)?;
-        self.def_to_symbol.get(def).map(|s| s.as_ref())
-    }
-
-    pub fn lookup_symbol_by_def(&self, def: &DefId) -> Option<&Symbol> {
-        self.def_to_symbol.get(def).map(|s| s.as_ref())
-    }
-
-    #[allow(dead_code)]
-    pub fn debug(&self) {
-        println!("Symbol table:");
-        println!("----------------");
-        for (id, def) in self.id_to_def.iter() {
-            if let Some(symbol) = self.def_to_symbol.get(def) {
-                println!("{} => {}: {}", id, def, symbol);
-            } else {
-                println!("{} => {} <NO SYMBOL FOUND>", id, def);
-            }
-        }
-    }
-
-    /// Register a new mapping of a fully-qualified symbol name (e.g. `Option::Some`)
-    /// to a Symbol, a descriptor of what that name refers to.
-    fn add_symbol(&mut self, id: &ItemId, fqsn: Fqsn, spec: SymbolSpec) {
-        let def_id = self.def_id_store.fresh();
-        let local_name = fqsn.last_elem();
-        let symbol = Rc::new(Symbol { fully_qualified_name: fqsn.clone(), local_name, spec, def_id });
-        self.symbol_trie.insert(&fqsn, def_id);
-        self.id_to_def.insert(*id, def_id);
-        self.def_to_symbol.insert(def_id, symbol);
-    }
-
-    fn populate_single_builtin(&mut self, fqsn: Fqsn, builtin: Builtin) {
-        let def_id = self.def_id_store.fresh();
-        let spec = SymbolSpec::Builtin(builtin);
-        let local_name = fqsn.last_elem();
-        let symbol = Rc::new(Symbol { fully_qualified_name: fqsn.clone(), local_name, spec, def_id });
-
-        self.symbol_trie.insert(&fqsn, def_id);
-        self.def_to_symbol.insert(def_id, symbol);
-    }
-}
-
-#[allow(dead_code)]
-#[derive(Debug, Clone)]
-pub struct Symbol {
-    fully_qualified_name: Fqsn,
-    local_name: Rc<String>,
-    spec: SymbolSpec,
-    def_id: DefId,
-}
-
-impl Symbol {
-    pub fn local_name(&self) -> &str {
-        self.local_name.as_ref()
-    }
-
-    pub fn def_id(&self) -> DefId {
-        self.def_id
-    }
-
-    pub fn spec(&self) -> SymbolSpec {
-        self.spec.clone()
-    }
-}
-
-impl fmt::Display for Symbol {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "<Local name: {}, {}, Spec: {}>", self.local_name(), self.fully_qualified_name, self.spec)
-    }
-}
-
-//TODO - I think I eventually want to draw a distinction between true global items
-//i.e. global vars, and items whose definitions are scoped. Right now there's a sense
-//in which Func, DataConstructor, RecordConstructor, and GlobalBinding are "globals",
-//whereas LocalVarible and FunctionParam have local scope. But right now, they all
-//get put into a common table, and all get DefId's from a common source.
-//
-//It would be good if individual functions could in parallel look up their own
-//local vars without interfering with other lookups. Also some type definitions
-//should be scoped in a similar way.
-//
-//Also it makes sense that non-globals should not use DefId's, particularly not
-//function parameters (even though they are currently assigned).
-#[derive(Debug, Clone)]
-pub enum SymbolSpec {
-    Builtin(Builtin),
-    Func { method: Option<crate::ast::TypeSingletonName> },
-    DataConstructor { tag: u32, type_id: TypeId },
-    RecordConstructor { tag: u32, type_id: TypeId },
-    GlobalBinding, //Only for global variables, not for function-local ones or ones within a `let` scope context
-    LocalVariable,
-    FunctionParam(u8),
-}
-
-impl fmt::Display for SymbolSpec {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        use self::SymbolSpec::*;
-        match self {
-            Builtin(b) => write!(f, "Builtin: {:?}", b),
-            Func { .. } => write!(f, "Func"),
-            DataConstructor { tag, type_id } => write!(f, "DataConstructor(tag: {}, type: {})", tag, type_id),
-            RecordConstructor { type_id, tag, .. } =>
-                write!(f, "RecordConstructor(tag: {})(<members> -> {})", tag, type_id),
-            GlobalBinding => write!(f, "GlobalBinding"),
-            LocalVariable => write!(f, "Local variable"),
-            FunctionParam(n) => write!(f, "Function param: {}", n),
-        }
-    }
-}

schala-lang/src/symbol_table/populator.rs

@@ -1,352 +0,0 @@
-use std::{
-    collections::{hash_map::Entry, HashMap, HashSet},
-    rc::Rc,
-    str::FromStr,
-};
-
-use super::{Fqsn, NameKind, NameSpec, ScopeSegment, SymbolError, SymbolSpec, SymbolTable, TypeKind};
-use crate::{
-    ast::{
-        Declaration, Expression, ExpressionKind, ItemId, Statement, StatementKind, TypeBody,
-        TypeSingletonName, Variant, VariantKind, AST,
-    },
-    builtin::Builtin,
-    parsing::Location,
-    type_inference::{self, PendingType, TypeBuilder, TypeContext, VariantBuilder},
-};
-
-pub(super) struct SymbolTablePopulator<'a> {
-    pub(super) type_context: &'a mut TypeContext,
-    pub(super) table: &'a mut SymbolTable,
-}
-
-impl<'a> SymbolTablePopulator<'a> {
-    /* note: this adds names for *forward reference* but doesn't actually create any types. solve that problem
-     * later */
-
-    fn add_symbol(&mut self, id: &ItemId, fqsn: Fqsn, spec: SymbolSpec) {
-        self.table.add_symbol(id, fqsn, spec)
-    }
-
-    /// This function traverses the AST and adds symbol table entries for
-    /// constants, functions, types, and modules defined within. This simultaneously
-    /// checks for dupicate definitions (and returns errors if discovered), and sets
-    /// up name tables that will be used by further parts of the compiler
-    pub fn populate_definition_tables(&mut self, ast: &AST) -> Vec<SymbolError> {
-        let mut scope_stack = vec![];
-        self.add_from_scope(ast.statements.as_ref(), &mut scope_stack, false)
-    }
-
-    fn add_from_scope(
-        &mut self,
-        statements: &[Statement<StatementKind>],
-        scope_stack: &mut Vec<ScopeSegment>,
-        function_scope: bool,
-    ) -> Vec<SymbolError> {
-        let mut errors = vec![];
-
-        for statement in statements {
-            let Statement { id, kind, location } = statement;
-            let location = *location;
-            if let Err(err) = self.add_single_statement(id, kind, location, scope_stack, function_scope) {
-                errors.push(err);
-            } else {
-                let decl = match kind {
-                    StatementKind::Declaration(decl) => decl,
-                    _ => continue,
-                };
-                // If there's an error with a name, don't recurse into subscopes of that name
-                let recursive_errs = match decl {
-                    Declaration::FuncDecl(signature, body) => {
-                        let new_scope = ScopeSegment::Name(signature.name.clone());
-                        scope_stack.push(new_scope);
-                        let output = self.add_from_scope(body.as_ref(), scope_stack, true);
-                        scope_stack.pop();
-                        output
-                    }
-                    Declaration::Module { name, items } => {
-                        let new_scope = ScopeSegment::Name(name.clone());
-                        scope_stack.push(new_scope);
-                        let output = self.add_from_scope(items.as_ref(), scope_stack, false);
-                        scope_stack.pop();
-                        output
-                    }
-                    Declaration::TypeDecl { name, body, mutable } => {
-                        let type_fqsn = Fqsn::from_scope_stack(scope_stack, name.name.clone());
-                        self.add_type_members(name, body, mutable, location, type_fqsn)
-                    }
-
-                    Declaration::Impl { type_name, interface_name: _, block } => {
-                        let mut errors = vec![];
-                        let new_scope = ScopeSegment::Name(Rc::new(format!("<impl-block>{}", type_name)));
-                        scope_stack.push(new_scope);
-
-                        for decl_stmt in block.iter() {
-                            let Statement { id, kind, location } = decl_stmt;
-                            let location = *location;
-                            match kind {
-                                decl @ Declaration::FuncDecl(signature, body) => {
-                                    let output =
-                                        self.add_single_declaration(id, decl, location, scope_stack, true);
-                                    if let Err(e) = output {
-                                        errors.push(e);
-                                    };
-                                    let new_scope = ScopeSegment::Name(signature.name.clone());
-                                    scope_stack.push(new_scope);
-                                    let output = self.add_from_scope(body.as_ref(), scope_stack, true);
-                                    scope_stack.pop();
-                                    errors.extend(output.into_iter());
-                                }
-                                _other => errors.push(SymbolError::BadImplBlockEntry),
-                            };
-                        }
-                        scope_stack.pop();
-                        errors
-                    }
-                    _ => vec![],
-                };
-                errors.extend(recursive_errs.into_iter());
-            }
-        }
-
-        errors
-    }
-
-    fn add_single_statement(
-        &mut self,
-        id: &ItemId,
-        kind: &StatementKind,
-        location: Location,
-        scope_stack: &[ScopeSegment],
-        function_scope: bool,
-    ) -> Result<(), SymbolError> {
-        match kind {
-            StatementKind::Declaration(decl) =>
-                self.add_single_declaration(id, decl, location, scope_stack, function_scope),
-            _ => return Ok(()),
-        }
-    }
-
-    fn add_single_declaration(
-        &mut self,
-        id: &ItemId,
-        decl: &Declaration,
-        location: Location,
-        scope_stack: &[ScopeSegment],
-        function_scope: bool,
-    ) -> Result<(), SymbolError> {
-        match decl {
-            Declaration::FuncSig(signature) => {
-                let fq_function = Fqsn::from_scope_stack(scope_stack, signature.name.clone());
-                self.table
-                    .fq_names
-                    .register(fq_function.clone(), NameSpec { location, kind: NameKind::Function })?;
-                self.table
-                    .types
-                    .register(fq_function.clone(), NameSpec { location, kind: TypeKind::Function })?;
-
-                self.add_symbol(id, fq_function, SymbolSpec::Func { method: None });
-            }
-            Declaration::FuncDecl(signature, ..) => {
-                let fn_name = &signature.name;
-                let fq_function = Fqsn::from_scope_stack(scope_stack, fn_name.clone());
-                self.table
-                    .fq_names
-                    .register(fq_function.clone(), NameSpec { location, kind: NameKind::Function })?;
-                self.table
-                    .types
-                    .register(fq_function.clone(), NameSpec { location, kind: TypeKind::Function })?;
-
-                self.add_symbol(id, fq_function, SymbolSpec::Func { method: None });
-            }
-            Declaration::TypeDecl { name, .. } => {
-                let fq_type = Fqsn::from_scope_stack(scope_stack, name.name.clone());
-                self.table.types.register(fq_type, NameSpec { location, kind: TypeKind::Constructor })?;
-            }
-            //TODO handle type aliases
-            Declaration::TypeAlias { .. } => (),
-            Declaration::Binding { name, .. } => {
-                let fq_binding = Fqsn::from_scope_stack(scope_stack, name.clone());
-                self.table
-                    .fq_names
-                    .register(fq_binding.clone(), NameSpec { location, kind: NameKind::Binding })?;
-                if !function_scope {
-                    self.add_symbol(id, fq_binding, SymbolSpec::GlobalBinding);
-                }
-            }
-            //TODO implement interfaces
-            Declaration::Interface { .. } => (),
-            Declaration::Impl { .. } => (),
-            Declaration::Module { name, .. } => {
-                let fq_module = Fqsn::from_scope_stack(scope_stack, name.clone());
-                self.table.fq_names.register(fq_module, NameSpec { location, kind: NameKind::Module })?;
-            }
-            Declaration::Annotation { name, arguments, inner } => {
-                let inner = inner.as_ref();
-                self.add_single_statement(
-                    &inner.id,
-                    &inner.kind,
-                    inner.location,
-                    scope_stack,
-                    function_scope,
-                )?;
-                self.process_annotation(name.as_ref(), arguments.as_slice(), scope_stack, inner)?;
-            }
-        }
-        Ok(())
-    }
-
-    fn process_annotation(
-        &mut self,
-        name: &str,
-        arguments: &[Expression],
-        scope_stack: &[ScopeSegment],
-        inner: &Statement<StatementKind>,
-    ) -> Result<(), SymbolError> {
-        if name == "register_builtin" {
-            if let Statement {
-                id: _,
-                location: _,
-                kind: StatementKind::Declaration(Declaration::FuncDecl(sig, _)),
-            } = inner
-            {
-                let fqsn = Fqsn::from_scope_stack(scope_stack, sig.name.clone());
-                let builtin_name = match arguments {
-                    [Expression { kind: ExpressionKind::Value(qname), .. }]
-                        if qname.components.len() == 1 =>
-                        qname.components[0].clone(),
-                    _ =>
-                        return Err(SymbolError::BadAnnotation {
-                            name: name.to_string(),
-                            msg: "Bad argument for register_builtin".to_string(),
-                        }),
-                };
-
-                let builtin =
-                    Builtin::from_str(builtin_name.as_str()).map_err(|_| SymbolError::BadAnnotation {
-                        name: name.to_string(),
-                        msg: format!("Invalid builtin: {}", builtin_name),
-                    })?;
-
-                self.table.populate_single_builtin(fqsn, builtin);
-                Ok(())
-            } else {
-                Err(SymbolError::BadAnnotation {
-                    name: name.to_string(),
-                    msg: "register_builtin not annotating a function".to_string(),
-                })
-            }
-        } else {
-            Err(SymbolError::UnknownAnnotation { name: name.to_string() })
-        }
-    }
-
-    fn add_type_members(
-        &mut self,
-        type_name: &TypeSingletonName,
-        type_body: &TypeBody,
-        _mutable: &bool,
-        location: Location,
-        type_fqsn: Fqsn,
-    ) -> Vec<SymbolError> {
-        let (variants, immediate_variant) = match type_body {
-            TypeBody::Variants(variants) => (variants.clone(), false),
-            TypeBody::ImmediateRecord { id, fields } => (
-                vec![Variant {
-                    id: *id,
-                    name: type_name.name.clone(),
-                    kind: VariantKind::Record(fields.clone()),
-                }],
-                true,
-            ),
-        };
-
-        // Check for duplicates before registering any types with the TypeContext
-        let mut seen_variants = HashSet::new();
-        let mut errors = vec![];
-
-        for variant in variants.iter() {
-            if seen_variants.contains(&variant.name) {
-                errors.push(SymbolError::DuplicateVariant {
-                    type_fqsn: type_fqsn.clone(),
-                    name: variant.name.as_ref().to_string(),
-                })
-            }
-            seen_variants.insert(variant.name.clone());
-
-            if let VariantKind::Record(ref members) = variant.kind {
-                let mut seen_members = HashMap::new();
-                for (member_name, _) in members.iter() {
-                    match seen_members.entry(member_name.as_ref()) {
-                        Entry::Occupied(o) => {
-                            let location = *o.get();
-                            errors.push(SymbolError::DuplicateRecord {
-                                type_fqsn: type_fqsn.clone(),
-                                location,
-                                record: variant.name.as_ref().to_string(),
-                                member: member_name.as_ref().to_string(),
-                            });
-                        }
-                        //TODO eventually this should track meaningful locations
-                        Entry::Vacant(v) => {
-                            v.insert(location);
-                        }
-                    }
-                }
-            }
-        }
-
-        if !errors.is_empty() {
-            return errors;
-        }
-
-        let mut type_builder = TypeBuilder::new(type_name.name.as_ref());
-
-        let mut variant_name_map = HashMap::new();
-        for variant in variants.iter() {
-            let Variant { name, kind, id } = variant;
-
-            variant_name_map.insert(name.clone(), id);
-
-            let mut variant_builder = VariantBuilder::new(name.as_ref());
-            match kind {
-                VariantKind::UnitStruct => (),
-                VariantKind::TupleStruct(items) =>
-                    for type_identifier in items {
-                        let pending: PendingType = type_identifier.into();
-                        variant_builder.add_member(pending);
-                    },
-                VariantKind::Record(members) =>
-                    for (field_name, type_identifier) in members.iter() {
-                        let pending: PendingType = type_identifier.into();
-                        variant_builder.add_record_member(field_name.as_ref(), pending);
-                    },
-            }
-            type_builder.add_variant(variant_builder);
-        }
-
-        let type_id = self.type_context.register_type(type_builder);
-        let type_definition = self.type_context.lookup_type(&type_id).unwrap();
-
-        // This index is guaranteed to be the correct tag
-        for (index, variant) in type_definition.variants.iter().enumerate() {
-            let id = variant_name_map.get(&variant.name).unwrap();
-            let tag = index as u32;
-            let spec = match &variant.members {
-                type_inference::VariantMembers::Unit => SymbolSpec::DataConstructor { tag, type_id },
-                type_inference::VariantMembers::Tuple(..) => SymbolSpec::DataConstructor { tag, type_id },
-                type_inference::VariantMembers::Record(..) => SymbolSpec::RecordConstructor { tag, type_id },
-            };
-            self.table.add_symbol(id, type_fqsn.extend(&variant.name), spec);
-        }
-
-        if immediate_variant {
-            let variant = &type_definition.variants[0];
-            let id = variant_name_map.get(&variant.name).unwrap();
-            let spec = SymbolSpec::RecordConstructor { tag: 0, type_id };
-            self.table.add_symbol(id, type_fqsn, spec);
-        }
-
-        vec![]
-    }
-}

schala-lang/src/symbol_table/resolver.rs

@@ -1,253 +0,0 @@
-use std::rc::Rc;
-
-use crate::{
-    ast::*,
-    symbol_table::{Fqsn, ScopeSegment, SymbolSpec, SymbolTable},
-    util::ScopeStack,
-};
-
-#[derive(Debug)]
-enum NameType {
-    //TODO eventually this needs to support closures
-    Param(u8),
-    LocalVariable(ItemId),
-    LocalFunction(ItemId),
-    Import(Fqsn),
-}
-
-type LexScope<'a> = ScopeStack<'a, Rc<String>, NameType, ScopeType>;
-
-#[derive(Debug)]
-enum ScopeType {
-    Function { name: Rc<String> },
-    Lambda,
-    PatternMatch,
-    ImplBlock,
-    //TODO add some notion of a let-like scope?
-}
-
-pub struct ScopeResolver<'a> {
-    symbol_table: &'a mut super::SymbolTable,
-    lexical_scopes: LexScope<'a>,
-}
-
-impl<'a> ScopeResolver<'a> {
-    pub fn new(symbol_table: &'a mut SymbolTable) -> Self {
-        let lexical_scopes = ScopeStack::new(None);
-        Self { symbol_table, lexical_scopes }
-    }
-
-    pub fn resolve(&mut self, ast: &AST) {
-        walk_ast(self, ast);
-    }
-
-    /// This method correctly modifies the id_to_def table (ItemId) to have the appropriate
-    /// mappings.
-    fn lookup_name_in_scope(&mut self, name: &QualifiedName) {
-        //TODO this method badly needs attention
-        let QualifiedName { id, components } = name;
-
-        let local_name = components.first().unwrap().clone();
-        let name_type = self.lexical_scopes.lookup(&local_name);
-        let fqsn = Fqsn { scopes: components.iter().map(|name| ScopeSegment::Name(name.clone())).collect() };
-        let def_id = self.symbol_table.symbol_trie.lookup(&fqsn);
-
-        //TODO handle a "partial" qualified name, and also handle it down in the pattern-matching
-        //section
-        if components.len() == 1 {
-            match name_type {
-                Some(NameType::Import(fqsn)) => {
-                    let def_id = self.symbol_table.symbol_trie.lookup(fqsn);
-
-                    if let Some(def_id) = def_id {
-                        self.symbol_table.id_to_def.insert(*id, def_id);
-                    }
-                }
-                Some(NameType::Param(n)) => {
-                    let spec = SymbolSpec::FunctionParam(*n);
-                    //TODO need to come up with a better solution for local variable FQSNs
-                    let lscope = ScopeSegment::Name(Rc::new("<local-param>".to_string()));
-                    let fqsn = Fqsn { scopes: vec![lscope, ScopeSegment::Name(local_name.clone())] };
-                    self.symbol_table.add_symbol(id, fqsn, spec);
-                }
-                Some(NameType::LocalFunction(item_id)) => {
-                    let def_id = self.symbol_table.id_to_def.get(item_id);
-                    if let Some(def_id) = def_id {
-                        let def_id = *def_id;
-                        self.symbol_table.id_to_def.insert(*id, def_id);
-                    }
-                }
-                Some(NameType::LocalVariable(item_id)) => {
-                    let def_id = self.symbol_table.id_to_def.get(item_id);
-                    if let Some(def_id) = def_id {
-                        let def_id = *def_id;
-                        self.symbol_table.id_to_def.insert(*id, def_id);
-                    }
-                }
-                None =>
-                    if let Some(def_id) = def_id {
-                        self.symbol_table.id_to_def.insert(*id, def_id);
-                    },
-            }
-        } else if let Some(def_id) = def_id {
-            self.symbol_table.id_to_def.insert(*id, def_id);
-        }
-    }
-}
-
-impl<'a> ASTVisitor for ScopeResolver<'a> {
-    // Import statements bring in a bunch of local names that all map to a specific FQSN.
-    // FQSNs map to a Symbol (or this is an error), Symbols have a DefId. So for every
-    // name we import, we map a local name (a string) to a NameType::ImportedDefinition(DefId).
-    fn import(&mut self, import_spec: &ImportSpecifier) -> Recursion {
-        let ImportSpecifier { ref path_components, ref imported_names, .. } = &import_spec;
-        match imported_names {
-            ImportedNames::All => {
-                let prefix =
-                    Fqsn { scopes: path_components.iter().map(|c| ScopeSegment::Name(c.clone())).collect() };
-                let members = self.symbol_table.symbol_trie.get_children(&prefix);
-                for fqsn in members.into_iter() {
-                    self.lexical_scopes.insert(fqsn.last_elem(), NameType::Import(fqsn));
-                }
-            }
-            ImportedNames::LastOfPath => {
-                let fqsn =
-                    Fqsn { scopes: path_components.iter().map(|c| ScopeSegment::Name(c.clone())).collect() };
-                self.lexical_scopes.insert(fqsn.last_elem(), NameType::Import(fqsn));
-            }
-            ImportedNames::List(ref names) => {
-                let fqsn_prefix: Vec<ScopeSegment> =
-                    path_components.iter().map(|c| ScopeSegment::Name(c.clone())).collect();
-                for name in names.iter() {
-                    let mut scopes = fqsn_prefix.clone();
-                    scopes.push(ScopeSegment::Name(name.clone()));
-                    let fqsn = Fqsn { scopes };
-                    self.lexical_scopes.insert(fqsn.last_elem(), NameType::Import(fqsn));
-                }
-            }
-        };
-        Recursion::Continue
-    }
-
-    fn declaration(&mut self, declaration: &Declaration, id: &ItemId) -> Recursion {
-        let cur_function_name = match self.lexical_scopes.get_name() {
-            //TODO this needs to be a fqsn
-            Some(ScopeType::Function { name }) => Some(name.clone()),
-            _ => None,
-        };
-        match declaration {
-            Declaration::FuncDecl(signature, block) => {
-                let param_names = signature.params.iter().map(|param| param.name.clone());
-                //TODO I'm 90% sure this is right, until I get to closures
-                //let mut new_scope = self.lexical_scopes.new_scope(Some(ScopeType::Function { name: signature.name.clone() }));
-                //TODO this will recurse unwantedly into scopes; need to pop an outer function
-                //scope off first before going into a non-closure scope
-                let mut new_scope =
-                    ScopeStack::new(Some(ScopeType::Function { name: signature.name.clone() }));
-
-                for (n, param) in param_names.enumerate() {
-                    new_scope.insert(param, NameType::Param(n as u8));
-                }
-
-                self.lexical_scopes.insert(signature.name.clone(), NameType::LocalFunction(*id));
-
-                let mut new_resolver =
-                    ScopeResolver { symbol_table: self.symbol_table, lexical_scopes: new_scope };
-                walk_block(&mut new_resolver, block);
-                Recursion::Stop
-            }
-            Declaration::Binding { name, .. } => {
-                if let Some(fn_name) = cur_function_name {
-                    // We are within a function scope
-                    let fqsn =
-                        Fqsn { scopes: vec![ScopeSegment::Name(fn_name), ScopeSegment::Name(name.clone())] };
-                    self.symbol_table.add_symbol(id, fqsn, SymbolSpec::LocalVariable);
-                    self.lexical_scopes.insert(name.clone(), NameType::LocalVariable(*id));
-                }
-                Recursion::Continue
-            }
-            Declaration::Impl { block, .. } => {
-                let new_scope = ScopeStack::new(Some(ScopeType::ImplBlock));
-                let mut new_resolver =
-                    ScopeResolver { symbol_table: self.symbol_table, lexical_scopes: new_scope };
-                for stmt in block.iter() {
-                    walk_declaration(&mut new_resolver, &stmt.kind, &stmt.id);
-                }
-                Recursion::Stop
-            }
-            _ => Recursion::Continue,
-        }
-    }
-
-    fn expression(&mut self, expression: &Expression) -> Recursion {
-        use ExpressionKind::*;
-        match &expression.kind {
-            Value(name) => {
-                self.lookup_name_in_scope(name);
-            }
-            NamedStruct { name, fields: _ } => {
-                self.lookup_name_in_scope(name);
-            }
-            Lambda { params, body, .. } => {
-                let param_names = params.iter().map(|param| param.name.clone());
-                //TODO need to properly handle closure scope, this is currently broken
-                //let mut new_scope = self.lexical_scopes.new_scope(Some(ScopeType::Function { name: signature.name.clone() }));
-                let mut new_scope = ScopeStack::new(Some(ScopeType::Lambda));
-
-                for (n, param) in param_names.enumerate() {
-                    new_scope.insert(param, NameType::Param(n as u8));
-                }
-
-                let mut new_resolver =
-                    ScopeResolver { symbol_table: self.symbol_table, lexical_scopes: new_scope };
-                walk_block(&mut new_resolver, body);
-                return Recursion::Stop;
-            }
-            IfExpression { discriminator, body } => {
-                if let Some(d) = discriminator.as_ref() {
-                    walk_expression(self, d);
-                }
-                let mut resolver = ScopeResolver {
-                    lexical_scopes: self.lexical_scopes.new_scope(Some(ScopeType::PatternMatch)),
-                    symbol_table: self.symbol_table,
-                };
-                walk_if_expr_body(&mut resolver, body);
-                return Recursion::Stop;
-            }
-            _ => (),
-        }
-        Recursion::Continue
-    }
-
-    fn pattern(&mut self, pat: &Pattern) -> Recursion {
-        use Pattern::*;
-
-        match pat {
-            Literal(..) | Ignored | TuplePattern(..) => (),
-            TupleStruct(name, _) | Record(name, _) => {
-                self.lookup_name_in_scope(name);
-            }
-            //TODO this isn't really the right syntax for a VarOrName
-            VarOrName(QualifiedName { id, components }) => {
-                if components.len() == 1 {
-                    //TODO need a better way to construct a FQSN from a QualifiedName
-                    let local_name: Rc<String> = components[0].clone();
-                    let lscope = ScopeSegment::Name(Rc::new("<local-case-match>".to_string()));
-                    let fqsn = Fqsn { scopes: vec![lscope, ScopeSegment::Name(local_name.clone())] };
-                    self.symbol_table.add_symbol(id, fqsn, SymbolSpec::LocalVariable);
-                    self.lexical_scopes.insert(local_name, NameType::LocalVariable(*id));
-                } else {
-                    let fqsn = Fqsn {
-                        scopes: components.iter().map(|name| ScopeSegment::Name(name.clone())).collect(),
-                    };
-                    let def_id = self.symbol_table.symbol_trie.lookup(&fqsn);
-
-                    if let Some(def_id) = def_id {
-                        self.symbol_table.id_to_def.insert(*id, def_id);
-                    }
-                }
-            }
-        };
-        Recursion::Continue
-    }
-}

schala-lang/src/symbol_table/symbol_trie.rs

@@ -1,70 +0,0 @@
-use std::{
-    collections::hash_map::DefaultHasher,
-    hash::{Hash, Hasher},
-};
-
-use radix_trie::{Trie, TrieCommon, TrieKey};
-
-use super::{DefId, Fqsn, ScopeSegment};
-
-#[derive(Debug)]
-pub struct SymbolTrie(Trie<Fqsn, DefId>);
-
-impl TrieKey for Fqsn {
-    fn encode_bytes(&self) -> Vec<u8> {
-        let mut hasher = DefaultHasher::new();
-        let mut output = vec![];
-        for segment in self.scopes.iter() {
-            let ScopeSegment::Name(s) = segment;
-            s.as_bytes().hash(&mut hasher);
-            output.extend_from_slice(&hasher.finish().to_be_bytes());
-        }
-        output
-    }
-}
-
-impl SymbolTrie {
-    pub fn new() -> SymbolTrie {
-        SymbolTrie(Trie::new())
-    }
-
-    pub fn insert(&mut self, fqsn: &Fqsn, def_id: DefId) {
-        self.0.insert(fqsn.clone(), def_id);
-    }
-
-    pub fn lookup(&self, fqsn: &Fqsn) -> Option<DefId> {
-        self.0.get(fqsn).cloned()
-    }
-
-    pub fn get_children(&self, fqsn: &Fqsn) -> Vec<Fqsn> {
-        let subtrie = match self.0.subtrie(fqsn) {
-            Some(s) => s,
-            None => return vec![],
-        };
-        let output: Vec<Fqsn> = subtrie.keys().filter(|cur_key| **cur_key != *fqsn).cloned().collect();
-        output
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-    use crate::symbol_table::Fqsn;
-
-    fn make_fqsn(strs: &[&str]) -> Fqsn {
-        Fqsn::from_strs(strs)
-    }
-
-    #[test]
-    fn test_trie_insertion() {
-        let id = DefId::default();
-        let mut trie = SymbolTrie::new();
-
-        trie.insert(&make_fqsn(&["unrelated", "thing"]), id);
-        trie.insert(&make_fqsn(&["outer", "inner"]), id);
-        trie.insert(&make_fqsn(&["outer", "inner", "still_inner"]), id);
-
-        let children = trie.get_children(&make_fqsn(&["outer", "inner"]));
-        assert_eq!(children.len(), 1);
-    }
-}

schala-lang/src/symbol_table/test.rs

@@ -1,314 +0,0 @@
-#![cfg(test)]
-use assert_matches::assert_matches;
-
-use super::*;
-use crate::util::quick_ast;
-
-fn add_symbols(src: &str) -> (SymbolTable, Result<(), Vec<SymbolError>>) {
-    let ast = quick_ast(src);
-    let mut symbol_table = SymbolTable::new();
-    let mut type_context = crate::type_inference::TypeContext::new();
-    let result = symbol_table.process_ast(&ast, &mut type_context);
-    (symbol_table, result)
-}
-
-fn make_fqsn(strs: &[&str]) -> Fqsn {
-    Fqsn::from_strs(strs)
-}
-
-#[test]
-fn basic_symbol_table() {
-    let src = "let a = 10; fn b() { 20 }";
-    let (symbols, _) = add_symbols(src);
-
-    fn make_fqsn(strs: &[&str]) -> Fqsn {
-        Fqsn::from_strs(strs)
-    }
-
-    symbols.fq_names.table.get(&make_fqsn(&["b"])).unwrap();
-
-    let src = "type Option<T> = Some(T) | None";
-    let (symbols, _) = add_symbols(src);
-
-    symbols.types.table.get(&make_fqsn(&["Option"])).unwrap();
-}
-
-#[test]
-fn no_function_definition_duplicates() {
-    let source = r#"
-  fn a() { 1 }
-  fn b() { 2 }
-  fn a() { 3 }
-  "#;
-    let (_, output) = add_symbols(source);
-    let errs = output.unwrap_err();
-    assert_matches!(&errs[..], [
-      SymbolError::DuplicateName { prev_name, ..}
-    ] if prev_name == &Fqsn::from_strs(&["a"])
-    );
-}
-
-#[test]
-fn no_variable_definition_duplicates() {
-    let source = r#"
-  let x = 9
-  let a = 20
-  let q = 39
-  let a = 30
-  let x = 34
-  "#;
-    let (_, output) = add_symbols(source);
-    let errs = output.unwrap_err();
-
-    assert_matches!(&errs[..], [
-      SymbolError::DuplicateName { prev_name: pn1, ..},
-      SymbolError::DuplicateName { prev_name: pn2, ..}
-    ] if pn1 == &Fqsn::from_strs(&["a"]) && pn2 == &Fqsn::from_strs(&["x"])
-    );
-}
-
-#[test]
-fn no_type_definition_duplicates() {
-    let source = r#"
-  let x = 9
-  type Food = Japchae | Burrito | Other
-  type Food = GoodJapchae | Breadfruit
-  "#;
-    let (_, output) = add_symbols(source);
-    let errs = output.unwrap_err();
-    let err = &errs[0];
-
-    match err {
-        SymbolError::DuplicateName { location: _, prev_name } => {
-            assert_eq!(prev_name, &Fqsn::from_strs(&["Food"]));
-
-            //TODO restore this Location test
-            //assert_eq!(location, &Location { line_num: 2, char_num: 2 });
-        }
-        _ => panic!(),
-    }
-}
-
-#[test]
-fn no_variant_duplicates() {
-    let source = r#"
-type Panda = FoolsGold | Kappa(i32) | Remix | Kappa | Thursday | Remix
-"#;
-    let (_, output) = add_symbols(source);
-    let errs = output.unwrap_err();
-    assert_eq!(errs.len(), 2);
-    assert_matches!(&errs[0], SymbolError::DuplicateVariant {
-        type_fqsn, name } if *type_fqsn == Fqsn::from_strs(&["Panda"]) &&
-        name == "Kappa");
-
-    assert_matches!(&errs[1], SymbolError::DuplicateVariant {
-        type_fqsn, name } if *type_fqsn == Fqsn::from_strs(&["Panda"]) &&
-        name == "Remix");
-}
-
-#[test]
-fn no_variable_definition_duplicates_in_function() {
-    let source = r#"
-  fn a() {
-    let a = 20
-    let b = 40
-    a + b
-  }
-
-  fn q() {
-    let a = 29
-    let x = 30
-    let x = 33
-  }
-  "#;
-    let (_, output) = add_symbols(source);
-    let errs = output.unwrap_err();
-    assert_matches!(&errs[..], [
-      SymbolError::DuplicateName { prev_name: pn1, ..},
-    ] if pn1 == &Fqsn::from_strs(&["q", "x"])
-    );
-}
-
-#[test]
-fn dont_falsely_detect_duplicates() {
-    let source = r#"
-  let a = 20;
-  fn some_func() {
-    let a = 40;
-    77
-  }
-  let q = 39
-  "#;
-    let (symbols, _) = add_symbols(source);
-
-    assert!(symbols.fq_names.table.get(&make_fqsn(&["a"])).is_some());
-    assert!(symbols.fq_names.table.get(&make_fqsn(&["some_func", "a"])).is_some());
-}
-
-#[test]
-fn enclosing_scopes() {
-    let source = r#"
-fn outer_func(x) {
-fn inner_func(arg) {
-  arg
-}
-x + inner_func(x)
-}"#;
-    let (symbols, _) = add_symbols(source);
-    assert!(symbols.fq_names.table.get(&make_fqsn(&["outer_func"])).is_some());
-    assert!(symbols.fq_names.table.get(&make_fqsn(&["outer_func", "inner_func"])).is_some());
-}
-
-#[test]
-fn enclosing_scopes_2() {
-    let source = r#"
-fn outer_func(x) {
-fn inner_func(arg) {
-  arg
-}
-
-fn second_inner_func() {
-  fn another_inner_func() {
-  }
-}
-
-inner_func(x)
-}
-"#;
-    let (symbols, _) = add_symbols(source);
-    assert!(symbols.fq_names.table.get(&make_fqsn(&["outer_func"])).is_some());
-    assert!(symbols.fq_names.table.get(&make_fqsn(&["outer_func", "inner_func"])).is_some());
-    assert!(symbols.fq_names.table.get(&make_fqsn(&["outer_func", "second_inner_func"])).is_some());
-    assert!(symbols
-        .fq_names
-        .table
-        .get(&make_fqsn(&["outer_func", "second_inner_func", "another_inner_func"]))
-        .is_some());
-}
-
-#[test]
-fn enclosing_scopes_3() {
-    let source = r#"
-fn outer_func(x) {
-
- fn inner_func(arg) {
-  arg
-}
-
-fn second_inner_func() {
-  fn another_inner_func() {
-  }
-  fn another_inner_func() {
-  }
-}
-
-inner_func(x)
-}"#;
-    let (_, output) = add_symbols(source);
-    let _err = output.unwrap_err();
-}
-
-#[test]
-fn modules() {
-    let source = r#"
-module stuff {
-  fn item() {
-  }
-}
-
-fn item()
-"#;
-
-    let (symbols, _) = add_symbols(source);
-    symbols.fq_names.table.get(&make_fqsn(&["stuff"])).unwrap();
-    symbols.fq_names.table.get(&make_fqsn(&["item"])).unwrap();
-    symbols.fq_names.table.get(&make_fqsn(&["stuff", "item"])).unwrap();
-}
-
-#[test]
-fn duplicate_modules() {
-    let source = r#"
-    module q {
-      fn foo() { 4 }
-    }
-
-    module a {
-      fn foo() { 334 }
-    }
-
-    module a {
-      fn sarat() { 39 }
-      fn foo() { 256.1 }
-    }
-    "#;
-    let (_, output) = add_symbols(source);
-    let errs = output.unwrap_err();
-
-    assert_matches!(&errs[..], [
-      SymbolError::DuplicateName { prev_name: pn1, ..},
-    ] if pn1 == &Fqsn::from_strs(&["a"])
-    );
-}
-
-#[test]
-fn duplicate_struct_members() {
-    let source = r#"
-      type Tarak = Tarak {
-        loujet: i32
-        ,
-        mets: i32,
-        mets: i32
-        ,
-      }
-    "#;
-
-    let (_, output) = add_symbols(source);
-    let errs = dbg!(output.unwrap_err());
-    assert_matches!(&errs[..], [
-      SymbolError::DuplicateRecord {
-        type_fqsn, member, record, ..},
-    ] if type_fqsn == &Fqsn::from_strs(&["Tarak"]) && member == "mets" && record == "Tarak"
-    );
-}
-
-#[test]
-fn method_definition_added_to_symbol_table() {
-    let source = r#"
-
-type Foo = { x: Int, y: Int }
-
-impl Foo {
-    fn hella() {
-        let a = 50
-        self.x + a
-    }
-}
-"#;
-    let (symbols, _) = add_symbols(source);
-    symbols.debug();
-    assert!(symbols.fq_names.table.get(&make_fqsn(&["<impl-block>Foo", "hella"])).is_some());
-    assert!(symbols.fq_names.table.get(&make_fqsn(&["<impl-block>Foo", "hella", "a"])).is_some());
-}
-
-#[test]
-fn duplicate_method_definitions_detected() {
-    let source = r#"
-
-type Foo = { x: Int, y: Int }
-
-impl Foo {
-    fn hella() {
-        self.x + 50
-    }
-
-    fn hella() {
-        self.x + 40
-    }
-}
-"#;
-    let (_symbols, output) = add_symbols(source);
-    let errs = output.unwrap_err();
-    assert_matches!(&errs[..], [
-      SymbolError::DuplicateName { prev_name: pn1, ..},
-    ] if pn1 == &Fqsn::from_strs(&["<impl-block>Foo", "hella"]));
-}

schala-lang/src/tree_walk_eval/evaluator.rs

@@ -1,513 +0,0 @@
-use std::rc::Rc;
-
-use super::{EvalResult, Memory, MemoryValue, Primitive, State};
-use crate::{
-    builtin::Builtin,
-    reduced_ir::{
-        Alternative, Callable, Expression, FunctionDefinition, Literal, Lookup, Pattern, ReducedIR, Statement,
-    },
-    type_inference::TypeContext,
-    util::ScopeStack,
-};
-
-#[derive(Debug)]
-enum StatementOutput {
-    Primitive(Primitive),
-    Nothing,
-}
-
-#[derive(Debug, Clone, Copy)]
-enum LoopControlFlow {
-    Break,
-    Continue,
-}
-
-pub struct Evaluator<'a, 'b> {
-    type_context: &'b TypeContext,
-    state: &'b mut State<'a>,
-    early_returning: bool,
-    loop_control: Option<LoopControlFlow>,
-}
-
-impl<'a, 'b> Evaluator<'a, 'b> {
-    pub(crate) fn new(state: &'b mut State<'a>, type_context: &'b TypeContext) -> Self {
-        Self { state, type_context, early_returning: false, loop_control: None }
-    }
-
-    pub fn evaluate(&mut self, reduced: ReducedIR, repl: bool) -> Vec<Result<String, String>> {
-        let mut acc = vec![];
-        for (def_id, function) in reduced.functions.into_iter() {
-            let mem = (&def_id).into();
-            self.state.memory.insert(mem, MemoryValue::Function(function));
-        }
-
-        for statement in reduced.entrypoint.into_iter() {
-            match self.statement(statement) {
-                Ok(StatementOutput::Primitive(output)) if repl =>
-                    acc.push(Ok(output.to_repl(self.type_context))),
-                Ok(_) => (),
-                Err(error) => {
-                    acc.push(Err(error.msg));
-                    return acc;
-                }
-            }
-        }
-        acc
-    }
-
-    fn block(&mut self, statements: Vec<Statement>) -> EvalResult<Primitive> {
-        let mut retval = None;
-        for stmt in statements.into_iter() {
-            match self.statement(stmt)? {
-                StatementOutput::Nothing => (),
-                StatementOutput::Primitive(prim) => {
-                    retval = Some(prim);
-                }
-            };
-            if self.early_returning {
-                break;
-            }
-            if self.loop_control.is_some() {
-                break;
-            }
-        }
-        Ok(if let Some(ret) = retval { ret } else { self.expression(Expression::unit())? })
-    }
-
-    fn statement(&mut self, stmt: Statement) -> EvalResult<StatementOutput> {
-        match stmt {
-            Statement::Binding { ref id, expr, constant: _ } => {
-                let evaluated = self.expression(expr)?;
-                self.state.memory.insert(id.into(), evaluated.into());
-                Ok(StatementOutput::Nothing)
-            }
-            Statement::Expression(expr) => {
-                let evaluated = self.expression(expr)?;
-                Ok(StatementOutput::Primitive(evaluated))
-            }
-            Statement::Return(expr) => {
-                let evaluated = self.expression(expr)?;
-                self.early_returning = true;
-                Ok(StatementOutput::Primitive(evaluated))
-            }
-            Statement::Break => {
-                self.loop_control = Some(LoopControlFlow::Break);
-                Ok(StatementOutput::Nothing)
-            }
-            Statement::Continue => {
-                self.loop_control = Some(LoopControlFlow::Continue);
-                Ok(StatementOutput::Nothing)
-            }
-        }
-    }
-
-    fn expression(&mut self, expression: Expression) -> EvalResult<Primitive> {
-        Ok(match expression {
-            Expression::Literal(lit) => Primitive::Literal(lit),
-            Expression::Tuple(items) => Primitive::Tuple(
-                items
-                    .into_iter()
-                    .map(|expr| self.expression(expr))
-                    .collect::<EvalResult<Vec<Primitive>>>()?,
-            ),
-            Expression::List(items) => Primitive::List(
-                items
-                    .into_iter()
-                    .map(|expr| self.expression(expr))
-                    .collect::<EvalResult<Vec<Primitive>>>()?,
-            ),
-            Expression::Lookup(kind) => match kind {
-                Lookup::Function(ref id) => {
-                    let mem = id.into();
-                    match self.state.memory.lookup(&mem) {
-                        // This just checks that the function exists in "memory" by ID, we don't
-                        // actually retrieve it until `apply_function()`
-                        Some(MemoryValue::Function(_)) => Primitive::Callable(Callable::UserDefined(*id)),
-                        x => return Err(format!("Function not found for id: {} : {:?}", id, x).into()),
-                    }
-                }
-                Lookup::Param(n) => {
-                    let mem = n.into();
-                    match self.state.memory.lookup(&mem) {
-                        Some(MemoryValue::Primitive(prim)) => prim.clone(),
-                        e => return Err(format!("Param lookup error, got {:?}", e).into()),
-                    }
-                }
-                Lookup::SelfParam => {
-                    let mem = Memory::self_param();
-                    match self.state.memory.lookup(&mem) {
-                        Some(MemoryValue::Primitive(prim)) => prim.clone(),
-                        e => return Err(format!("SelfParam lookup error, got {:?}", e).into()),
-                    }
-                }
-                Lookup::LocalVar(ref id) | Lookup::GlobalVar(ref id) => {
-                    let mem = id.into();
-                    match self.state.memory.lookup(&mem) {
-                        Some(MemoryValue::Primitive(expr)) => expr.clone(),
-                        _ =>
-                            return Err(
-                                format!("Nothing found for local/gloval variable lookup {}", id).into()
-                            ),
-                    }
-                }
-            },
-            Expression::Assign { ref lval, box rval } => {
-                let mem = lval.into();
-                let evaluated = self.expression(rval)?;
-                println!("Inserting {:?} into {:?}", evaluated, mem);
-                self.state.memory.insert(mem, MemoryValue::Primitive(evaluated));
-                Primitive::unit()
-            }
-            Expression::Call { box f, args } => self.call_expression(f, args, None)?,
-            Expression::CallMethod { box f, args, box self_expr } =>
-                self.call_expression(f, args, Some(self_expr))?,
-            Expression::Callable(Callable::DataConstructor { type_id, tag }) => {
-                let arity = self.type_context.lookup_variant_arity(&type_id, tag).unwrap();
-                if arity == 0 {
-                    Primitive::Object { type_id, tag, items: vec![], ordered_fields: None }
-                } else {
-                    Primitive::Callable(Callable::DataConstructor { type_id, tag })
-                }
-            }
-            Expression::Callable(func) => Primitive::Callable(func),
-            Expression::Conditional { box cond, then_clause, else_clause } => {
-                let cond = self.expression(cond)?;
-                match cond {
-                    Primitive::Literal(Literal::Bool(true)) => self.block(then_clause)?,
-                    Primitive::Literal(Literal::Bool(false)) => self.block(else_clause)?,
-                    v => return Err(format!("Non-boolean value {:?} in if-statement", v).into()),
-                }
-            }
-            Expression::CaseMatch { box cond, alternatives } =>
-                self.case_match_expression(cond, alternatives)?,
-            Expression::Index { box indexee, box indexer } => {
-                let indexee = self.expression(indexee)?;
-                let indexer = self.expression(indexer)?;
-                match (indexee, indexer) {
-                    (Primitive::List(items), Primitive::Literal(Literal::Nat(n))) =>
-                        match items.get(n as usize) {
-                            Some(item) => item.clone(),
-                            None => return Err(format!("Invalid index {} for this value", n).into()),
-                        },
-                    _ => return Err("Invalid index type".to_string().into()),
-                }
-            }
-            Expression::Loop { box cond, statements } => self.loop_expression(cond, statements)?,
-            Expression::ReductionError(e) => return Err(e.into()),
-            Expression::Access { name, box expr } => {
-                let expr = self.expression(expr)?;
-                match expr {
-                    Primitive::Object { items, ordered_fields: Some(ordered_fields), .. } => {
-                        let idx = match ordered_fields.iter().position(|s| s == &name) {
-                            Some(idx) => idx,
-                            None => return Err(format!("Field `{}` not found", name).into()),
-                        };
-
-                        let item = match items.get(idx) {
-                            Some(item) => item,
-                            None => return Err(format!("Field lookup `{}` failed", name).into()),
-                        };
-
-                        item.clone()
-                    }
-                    e =>
-                        return Err(
-                            format!("Trying to do a field lookup on a non-object value: {:?}", e).into()
-                        ),
-                }
-            }
-        })
-    }
-
-    fn loop_expression(&mut self, cond: Expression, statements: Vec<Statement>) -> EvalResult<Primitive> {
-        let existing = self.loop_control;
-        let output = self.loop_expression_inner(cond, statements);
-        self.loop_control = existing;
-        output
-    }
-
-    fn loop_expression_inner(
-        &mut self,
-        cond: Expression,
-        statements: Vec<Statement>,
-    ) -> EvalResult<Primitive> {
-        loop {
-            let cond = self.expression(cond.clone())?;
-            println!("COND: {:?}", cond);
-            match cond {
-                Primitive::Literal(Literal::Bool(true)) => (),
-                Primitive::Literal(Literal::Bool(false)) => break,
-                e => return Err(format!("Loop condition evaluates to non-boolean: {:?}", e).into()),
-            };
-            //TODO eventually loops shoudl be able to return something
-            let _output = self.block(statements.clone())?;
-            match self.loop_control {
-                None => (),
-                Some(LoopControlFlow::Continue) => {
-                    self.loop_control = None;
-                }
-                Some(LoopControlFlow::Break) => {
-                    break;
-                }
-            }
-        }
-        Ok(Primitive::unit())
-    }
-
-    fn case_match_expression(
-        &mut self,
-        cond: Expression,
-        alternatives: Vec<Alternative>,
-    ) -> EvalResult<Primitive> {
-        fn matches(scrut: &Primitive, pat: &Pattern, scope: &mut ScopeStack<Memory, MemoryValue>) -> bool {
-            match pat {
-                Pattern::Ignored => true,
-                Pattern::Binding(ref def_id) => {
-                    let mem = def_id.into();
-                    scope.insert(mem, MemoryValue::Primitive(scrut.clone())); //TODO make sure this doesn't cause problems with nesting
-                    true
-                }
-                Pattern::Literal(pat_literal) =>
-                    if let Primitive::Literal(scrut_literal) = scrut {
-                        pat_literal == scrut_literal
-                    } else {
-                        false
-                    },
-                Pattern::Tuple { subpatterns, tag } => match tag {
-                    None => match scrut {
-                        Primitive::Tuple(items) if items.len() == subpatterns.len() => items
-                            .iter()
-                            .zip(subpatterns.iter())
-                            .all(|(item, subpat)| matches(item, subpat, scope)),
-                        _ => false, //TODO should be a type error
-                    },
-                    Some(pattern_tag) => match scrut {
-                        //TODO should test type_ids for runtime type checking, once those work
-                        Primitive::Object { tag, items, .. }
-                            if tag == pattern_tag && items.len() == subpatterns.len() =>
-                            items
-                                .iter()
-                                .zip(subpatterns.iter())
-                                .all(|(item, subpat)| matches(item, subpat, scope)),
-                        _ => false,
-                    },
-                },
-                Pattern::Record { tag: pattern_tag, subpatterns } => match scrut {
-                    //TODO several types of possible error here
-                    Primitive::Object { tag, items, ordered_fields: Some(ordered_fields), .. }
-                        if tag == pattern_tag =>
-                        subpatterns.iter().all(|(field_name, subpat)| {
-                            let idx = ordered_fields
-                                .iter()
-                                .position(|field| field.as_str() == field_name.as_ref())
-                                .unwrap();
-                            let item = &items[idx];
-                            matches(item, subpat, scope)
-                        }),
-                    _ => false,
-                },
-            }
-        }
-        let cond = self.expression(cond)?;
-
-        for alt in alternatives.into_iter() {
-            let mut new_scope = self.state.memory.new_scope(None);
-            if matches(&cond, &alt.pattern, &mut new_scope) {
-                let mut new_state = State { memory: new_scope };
-                let mut evaluator = Evaluator::new(&mut new_state, self.type_context);
-                let output = evaluator.block(alt.item);
-                self.early_returning = evaluator.early_returning;
-                return output;
-            }
-        }
-        Err("No valid match in match expression".into())
-    }
-
-    //TODO need to do something with self_expr to make method invocations actually work
-    fn call_expression(
-        &mut self,
-        f: Expression,
-        args: Vec<Expression>,
-        self_expr: Option<Expression>,
-    ) -> EvalResult<Primitive> {
-        let func = match self.expression(f)? {
-            Primitive::Callable(func) => func,
-            other => return Err(format!("Trying to call non-function value: {:?}", other).into()),
-        };
-        match func {
-            Callable::Builtin(builtin) => self.apply_builtin(builtin, args),
-            Callable::UserDefined(def_id) => {
-                let mem = (&def_id).into();
-                match self.state.memory.lookup(&mem) {
-                    Some(MemoryValue::Function(FunctionDefinition { body })) => {
-                        let body = body.clone(); //TODO ideally this clone would not happen
-                        self.apply_function(body, args, self_expr)
-                    }
-                    e => Err(format!("Error looking up function with id {}: {:?}", def_id, e).into()),
-                }
-            }
-            Callable::Lambda { arity, body } => {
-                if arity as usize != args.len() {
-                    return Err(format!(
-                        "Lambda expression requries {} arguments, only {} provided",
-                        arity,
-                        args.len()
-                    )
-                    .into());
-                }
-                self.apply_function(body, args, None)
-            }
-            Callable::DataConstructor { type_id, tag } => {
-                let arity = self.type_context.lookup_variant_arity(&type_id, tag).unwrap();
-                if arity as usize != args.len() {
-                    return Err(format!(
-                        "Constructor expression requries {} arguments, only {} provided",
-                        arity,
-                        args.len()
-                    )
-                    .into());
-                }
-
-                let mut items: Vec<Primitive> = vec![];
-                for arg in args.into_iter() {
-                    items.push(self.expression(arg)?);
-                }
-                Ok(Primitive::Object { type_id, tag, items, ordered_fields: None })
-            }
-            Callable::RecordConstructor { type_id, tag, field_order } => {
-                //TODO maybe I'll want to do a runtime check of the evaluated fields
-                /*
-                let record_members = self.type_context.lookup_record_members(type_id, tag)
-                    .ok_or(format!("Runtime record lookup for: {} {} not found", type_id, tag).into())?;
-                */
-
-                let mut items: Vec<Primitive> = vec![];
-                for arg in args.into_iter() {
-                    items.push(self.expression(arg)?);
-                }
-                Ok(Primitive::Object { type_id, tag, items, ordered_fields: Some(field_order) })
-            }
-        }
-    }
-
-    fn apply_builtin(&mut self, builtin: Builtin, args: Vec<Expression>) -> EvalResult<Primitive> {
-        use Builtin::*;
-        use Literal::*;
-        use Primitive::Literal as Lit;
-
-        let evaled_args: EvalResult<Vec<Primitive>> =
-            args.into_iter().map(|arg| self.expression(arg)).collect();
-        let evaled_args = evaled_args?;
-
-        Ok(match (builtin, evaled_args.as_slice()) {
-            /* builtin functions */
-            (IOPrint, &[ref anything]) => {
-                print!("{}", anything.to_repl(self.type_context));
-                Primitive::Tuple(vec![])
-            }
-            (IOPrintLn, &[ref anything]) => {
-                println!("{}", anything.to_repl(self.type_context));
-                Primitive::Tuple(vec![])
-            }
-            (IOGetLine, &[]) => {
-                let mut buf = String::new();
-                std::io::stdin().read_line(&mut buf).expect("Error readling line in 'getline'");
-                StringLit(Rc::new(buf.trim().to_string())).into()
-            }
-            /* Binops */
-            (binop, &[ref lhs, ref rhs]) => match (binop, lhs, rhs) {
-                // TODO need a better way of handling these literals
-                (Add, Lit(Nat(l)), Lit(Nat(r))) => Nat(l + r).into(),
-                (Add, Lit(Int(l)), Lit(Int(r))) => Int(l + r).into(),
-                (Add, Lit(Nat(l)), Lit(Int(r))) => Int((*l as i64) + (*r as i64)).into(),
-                (Add, Lit(Int(l)), Lit(Nat(r))) => Int((*l as i64) + (*r as i64)).into(),
-                (Concatenate, Lit(StringLit(ref s1)), Lit(StringLit(ref s2))) =>
-                    StringLit(Rc::new(format!("{}{}", s1, s2))).into(),
-                (Subtract, Lit(Nat(l)), Lit(Nat(r))) => Nat(l - r).into(),
-                (Multiply, Lit(Nat(l)), Lit(Nat(r))) => Nat(l * r).into(),
-                (Divide, Lit(Nat(l)), Lit(Nat(r))) => Float((*l as f64) / (*r as f64)).into(),
-                (Quotient, Lit(Nat(l)), Lit(Nat(r))) =>
-                    if *r == 0 {
-                        return Err("Divide-by-zero error".into());
-                    } else {
-                        Nat(l / r).into()
-                    },
-                (Modulo, Lit(Nat(l)), Lit(Nat(r))) => Nat(l % r).into(),
-                (Exponentiation, Lit(Nat(l)), Lit(Nat(r))) => Nat(l ^ r).into(),
-                (BitwiseAnd, Lit(Nat(l)), Lit(Nat(r))) => Nat(l & r).into(),
-                (BitwiseOr, Lit(Nat(l)), Lit(Nat(r))) => Nat(l | r).into(),
-
-                /* comparisons */
-                (Equality, Lit(Nat(l)), Lit(Nat(r))) => Bool(l == r).into(),
-                (Equality, Lit(Int(l)), Lit(Int(r))) => Bool(l == r).into(),
-                (Equality, Lit(Float(l)), Lit(Float(r))) => Bool(l == r).into(),
-                (Equality, Lit(Bool(l)), Lit(Bool(r))) => Bool(l == r).into(),
-                (Equality, Lit(StringLit(ref l)), Lit(StringLit(ref r))) => Bool(l == r).into(),
-
-                (NotEqual, Lit(Nat(l)), Lit(Nat(r))) => Bool(l != r).into(),
-                (NotEqual, Lit(Int(l)), Lit(Int(r))) => Bool(l != r).into(),
-                (NotEqual, Lit(Float(l)), Lit(Float(r))) => Bool(l != r).into(),
-                (NotEqual, Lit(Bool(l)), Lit(Bool(r))) => Bool(l != r).into(),
-                (NotEqual, Lit(StringLit(ref l)), Lit(StringLit(ref r))) => Bool(l != r).into(),
-
-                (LessThan, Lit(Nat(l)), Lit(Nat(r))) => Bool(l < r).into(),
-                (LessThan, Lit(Int(l)), Lit(Int(r))) => Bool(l < r).into(),
-                (LessThan, Lit(Float(l)), Lit(Float(r))) => Bool(l < r).into(),
-
-                (LessThanOrEqual, Lit(Nat(l)), Lit(Nat(r))) => Bool(l <= r).into(),
-                (LessThanOrEqual, Lit(Int(l)), Lit(Int(r))) => Bool(l <= r).into(),
-                (LessThanOrEqual, Lit(Float(l)), Lit(Float(r))) => Bool(l <= r).into(),
-
-                (GreaterThan, Lit(Nat(l)), Lit(Nat(r))) => Bool(l > r).into(),
-                (GreaterThan, Lit(Int(l)), Lit(Int(r))) => Bool(l > r).into(),
-                (GreaterThan, Lit(Float(l)), Lit(Float(r))) => Bool(l > r).into(),
-
-                (GreaterThanOrEqual, Lit(Nat(l)), Lit(Nat(r))) => Bool(l >= r).into(),
-                (GreaterThanOrEqual, Lit(Int(l)), Lit(Int(r))) => Bool(l >= r).into(),
-                (GreaterThanOrEqual, Lit(Float(l)), Lit(Float(r))) => Bool(l >= r).into(),
-
-                (binop, lhs, rhs) =>
-                    return Err(format!("Invalid binop expression {:?} {:?} {:?}", lhs, binop, rhs).into()),
-            },
-            (prefix, &[ref arg]) => match (prefix, arg) {
-                (BooleanNot, Lit(Bool(true))) => Bool(false),
-                (BooleanNot, Lit(Bool(false))) => Bool(true),
-                (Negate, Lit(Nat(n))) => Int(-(*n as i64)),
-                (Negate, Lit(Int(n))) => Int(-(*n as i64)),
-                (Negate, Lit(Float(f))) => Float(-(*f as f64)),
-                (Increment, Lit(Int(n))) => Int(*n),
-                (Increment, Lit(Nat(n))) => Nat(*n),
-                _ => return Err("No valid prefix op".into()),
-            }
-            .into(),
-            (x, args) => return Err(format!("bad or unimplemented builtin {:?} | {:?}", x, args).into()),
-        })
-    }
-
-    fn apply_function(
-        &mut self,
-        body: Vec<Statement>,
-        args: Vec<Expression>,
-        self_expr: Option<Expression>,
-    ) -> EvalResult<Primitive> {
-        let self_expr = if let Some(expr) = self_expr { Some(self.expression(expr)?) } else { None };
-        let mut evaluated_args: Vec<Primitive> = vec![];
-        for arg in args.into_iter() {
-            evaluated_args.push(self.expression(arg)?);
-        }
-
-        let mut frame_state = State { memory: self.state.memory.new_scope(None) };
-        let mut evaluator = Evaluator::new(&mut frame_state, self.type_context);
-
-        if let Some(evaled) = self_expr {
-            let mem = Memory::self_param();
-            evaluator.state.memory.insert(mem, MemoryValue::Primitive(evaled));
-        }
-        for (n, evaled) in evaluated_args.into_iter().enumerate() {
-            let n = n as u8;
-            let mem = n.into();
-            evaluator.state.memory.insert(mem, MemoryValue::Primitive(evaled));
-        }
-        evaluator.block(body)
-    }
-}

schala-lang/src/tree_walk_eval/mod.rs

@@ -1,173 +0,0 @@
-use std::{convert::From, fmt::Write};
-
-use crate::{
-    reduced_ir::{Callable, Expression, FunctionDefinition, Literal, ReducedIR},
-    symbol_table::DefId,
-    type_inference::{TypeContext, TypeId},
-    util::{delim_wrapped, ScopeStack},
-};
-
-mod evaluator;
-mod test;
-
-type EvalResult<T> = Result<T, RuntimeError>;
-
-#[derive(Debug)]
-pub struct State<'a> {
-    memory: ScopeStack<'a, Memory, MemoryValue>,
-}
-
-//TODO - eh, I dunno, maybe it doesn't matter exactly how memory works in the tree-walking
-//evaluator
-#[derive(Debug, PartialEq, Eq, Hash, Clone)]
-enum Memory {
-    Index(u32),
-}
-
-impl Memory {
-    fn self_param() -> Self {
-        Memory::Index(3_999_999)
-    }
-}
-
-// This is for function param lookups, and is a hack
-impl From<u8> for Memory {
-    fn from(n: u8) -> Self {
-        Memory::Index(4_000_000 + (n as u32))
-    }
-}
-
-impl From<&DefId> for Memory {
-    fn from(id: &DefId) -> Self {
-        Self::Index(id.as_u32())
-    }
-}
-
-#[derive(Debug)]
-struct RuntimeError {
-    msg: String,
-}
-
-impl From<String> for RuntimeError {
-    fn from(msg: String) -> Self {
-        Self { msg }
-    }
-}
-
-impl From<&str> for RuntimeError {
-    fn from(msg: &str) -> Self {
-        Self { msg: msg.to_string() }
-    }
-}
-
-impl RuntimeError {
-    #[allow(dead_code)]
-    fn get_msg(&self) -> String {
-        format!("Runtime error: {}", self.msg)
-    }
-}
-
-/// Anything that can be stored in memory; that is, a function definition, or a fully-evaluated
-/// program value.
-#[derive(Debug)]
-enum MemoryValue {
-    Function(FunctionDefinition),
-    Primitive(Primitive),
-}
-
-impl From<Primitive> for MemoryValue {
-    fn from(prim: Primitive) -> Self {
-        Self::Primitive(prim)
-    }
-}
-
-#[derive(Debug)]
-enum RuntimeValue {
-    Expression(Expression),
-    Evaluated(Primitive),
-}
-
-impl From<Expression> for RuntimeValue {
-    fn from(expr: Expression) -> Self {
-        Self::Expression(expr)
-    }
-}
-
-impl From<Primitive> for RuntimeValue {
-    fn from(prim: Primitive) -> Self {
-        Self::Evaluated(prim)
-    }
-}
-
-/// A fully-reduced value
-#[derive(Debug, Clone)]
-enum Primitive {
-    Tuple(Vec<Primitive>),
-    List(Vec<Primitive>),
-    Literal(Literal),
-    Callable(Callable),
-    Object { type_id: TypeId, tag: u32, ordered_fields: Option<Vec<String>>, items: Vec<Primitive> },
-}
-
-impl Primitive {
-    fn to_repl(&self, type_context: &TypeContext) -> String {
-        match self {
-            Primitive::Object { type_id, items, tag, ordered_fields: _ } if items.is_empty() =>
-                type_context.variant_local_name(type_id, *tag).unwrap().to_string(),
-            Primitive::Object { type_id, items, tag, ordered_fields: None } => {
-                format!(
-                    "{}{}",
-                    type_context.variant_local_name(type_id, *tag).unwrap(),
-                    delim_wrapped('(', ')', items.iter().map(|item| item.to_repl(type_context)))
-                )
-            }
-            Primitive::Object { type_id, items, tag, ordered_fields: Some(fields) } => {
-                let mut buf = format!("{} {{ ", type_context.variant_local_name(type_id, *tag).unwrap());
-                for item in fields.iter().zip(items.iter()).map(Some).intersperse(None) {
-                    match item {
-                        Some((name, val)) => write!(buf, "{}: {}", name, val.to_repl(type_context)).unwrap(),
-                        None => write!(buf, ", ").unwrap(),
-                    }
-                }
-                write!(buf, " }}").unwrap();
-                buf
-            }
-            Primitive::Literal(lit) => match lit {
-                Literal::Nat(n) => format!("{}", n),
-                Literal::Int(i) => format!("{}", i),
-                Literal::Float(f) => format!("{}", f),
-                Literal::Bool(b) => format!("{}", b),
-                Literal::StringLit(s) => format!("\"{}\"", s),
-            },
-            Primitive::Tuple(terms) => delim_wrapped('(', ')', terms.iter().map(|x| x.to_repl(type_context))),
-            Primitive::List(terms) => delim_wrapped('[', ']', terms.iter().map(|x| x.to_repl(type_context))),
-            Primitive::Callable(..) => "<some-callable>".to_string(),
-        }
-    }
-
-    fn unit() -> Self {
-        Primitive::Tuple(vec![])
-    }
-}
-
-impl From<Literal> for Primitive {
-    fn from(lit: Literal) -> Self {
-        Primitive::Literal(lit)
-    }
-}
-
-impl<'a> State<'a> {
-    pub fn new() -> Self {
-        Self { memory: ScopeStack::new(Some("global".to_string())) }
-    }
-
-    pub fn evaluate(
-        &mut self,
-        reduced: ReducedIR,
-        type_context: &TypeContext,
-        repl: bool,
-    ) -> Vec<Result<String, String>> {
-        let mut evaluator = evaluator::Evaluator::new(self, type_context);
-        evaluator.evaluate(reduced, repl)
-    }
-}

schala-lang/src/tree_walk_eval/test.rs

@@ -1,564 +0,0 @@
-#![cfg(test)]
-use pretty_assertions::assert_eq;
-use test_case::test_case;
-
-use crate::{
-    symbol_table::SymbolTable,
-    tree_walk_eval::{evaluator::Evaluator, State},
-    type_inference::TypeContext,
-};
-
-fn evaluate_input(input: &str) -> Result<String, String> {
-    let ast = crate::util::quick_ast(input);
-    let mut symbol_table = SymbolTable::new();
-    let mut type_context = TypeContext::new();
-
-    symbol_table.process_ast(&ast, &mut type_context).unwrap();
-
-    let reduced_ir = crate::reduced_ir::reduce(&ast, &symbol_table, &type_context);
-    reduced_ir.debug(&symbol_table);
-    println!("========");
-    symbol_table.debug();
-
-    let mut state = State::new();
-    let mut evaluator = Evaluator::new(&mut state, &type_context);
-    let mut outputs = evaluator.evaluate(reduced_ir, true);
-    outputs.pop().unwrap()
-}
-
-fn eval_assert(input: &str, expected: &str) {
-    assert_eq!(evaluate_input(input), Ok(expected.to_string()));
-}
-
-fn eval_assert_failure(input: &str, expected: &str) {
-    assert_eq!(evaluate_input(input), Err(expected.to_string()));
-}
-
-#[test]
-fn test_basic_eval() {
-    eval_assert("1 + 2", "3");
-    eval_assert("let mut a = 1; a = 2", "()");
-    eval_assert("let mut a = 1; a = a + 2; a", "3");
-}
-
-#[test]
-fn op_eval() {
-    eval_assert("-13", "-13");
-    eval_assert("10 - 2", "8");
-}
-
-#[test]
-fn function_eval() {
-    eval_assert("fn oi(x) { x + 1 }; oi(4)", "5");
-    eval_assert("fn oi(x) { x + 1 }; oi(1+2)", "4");
-}
-
-#[test]
-fn scopes() {
-    let scope_ok = r#"
-    let a = 20
-    fn haha() {
-      let something = 38
-      let a = 10
-      a
-    }
-    haha()
-    "#;
-
-    eval_assert(scope_ok, "10");
-
-    let scope_ok = r#"
-    let a = 20
-    fn queque() {
-      let a = 10
-      a
-    }
-    a
-    "#;
-    eval_assert(scope_ok, "20");
-}
-
-#[test]
-fn eval_scopes_2() {
-    eval_assert(
-        r#"
-fn trad() {
-    let a = 10
-    fn jinner() {
-        let b = 20
-        b
-    }
-
-    a + jinner()
-}
-trad()"#,
-        "30",
-    );
-
-    let err = "No symbol found for name: `a`";
-
-    eval_assert_failure(
-        r#"
-fn trad() {
-    let a = 10
-    fn inner() {
-        let b = 20
-        a + b
-    }
-
-    inner()
-}
-
-trad()
-"#,
-        err,
-    );
-}
-
-#[test]
-fn adt_output_1() {
-    let source = r#"
-
-type Option<T> = Some(T) | None
-let a = Option::None
-let b = Option::Some(10)
-(b, a)
-"#;
-    eval_assert(source, "(Some(10), None)");
-}
-
-#[test]
-fn adt_output_2() {
-    let source = r#"
-type Gobble = Unknown | Rufus { a: Int, torrid: Nat }
-let b = Gobble::Rufus { a: 3, torrid: 99 }
-b
-    "#;
-    eval_assert(source, "Rufus { a: 3, torrid: 99 }");
-
-    let source = r#"
-type Gobble = Unknown | Rufus { a: Int, torrid: Nat }
-let b = Gobble::Rufus { torrid: 3, a: 84 }
-b
-    "#;
-    eval_assert(source, "Rufus { a: 84, torrid: 3 }");
-
-    let source = r#"
-type Gobble = Unknown | Rufus { a: Int, torrid: Nat }
-let b = Gobble::Rufus { a: 84 }
-b
-    "#;
-    eval_assert_failure(source, "Field torrid not specified for record Gobble::Rufus");
-}
-
-#[test]
-fn basic_if_statement() {
-    let source = r#"
-    let a = 10
-    let b = 10
-    if a == b then { 69 } else { 420 }
-    "#;
-    eval_assert(source, "69");
-}
-
-#[test]
-fn basic_patterns_1() {
-    let source = r#"
-let x = 10
-let a = if x is 10 then { 255 } else { 256 }
-let b = if 23 is 99 then { 255 } else { 256 }
-let c = if true is false then { 9 } else { 10 }
-let d = if "xxx" is "yyy" then { 20 } else { 30 }
-(a, b, c, d)
-    "#;
-    eval_assert(source, "(255, 256, 10, 30)");
-}
-
-#[test_case("sanchez", "1")]
-#[test_case("mouri", "2")]
-#[test_case("hella", "3")]
-#[test_case("cyrus", "4")]
-fn basic_patterns_2(input: &str, expected: &str) {
-    let mut source = format!(r#"let x = "{}""#, input);
-    source.push_str(
-        r#"
-if x {
-    is "sanchez" then 1
-    is "mouri" then 2
-    is "hella" then 3
-    is _ then 4
-}
-"#,
-    );
-    eval_assert(&source, expected);
-}
-
-#[test_case(r#"(45, "panda", false, 2.2)"#, r#""yes""#)]
-#[test_case(r#"(99, "panda", false, -2.45)"#, r#""maybe""#)]
-fn tuple_patterns(input: &str, expected: &str) {
-    let mut source = format!("let x = {}", input);
-    source.push_str(
-        r#"
-if x {
-    is (45, "pablo", _, 28.4) then "no"
-    is (_, "panda", _, 2.2) then "yes"
-    is _ then "maybe"
-}"#,
-    );
-
-    eval_assert(&source, expected);
-}
-
-#[test]
-fn record_patterns_1() {
-    let source = r#"
-type Ara = Kueh { a: Int, b: String } | Morbuk
-
-let alpha = Ara::Kueh { a: 10, b: "sanchez" }
-if alpha {
-    is Ara::Kueh { a, b } then (b, a)
-    is _ then ("nooo", 8888)
-}"#;
-    eval_assert(source, r#"("sanchez", 10)"#);
-}
-
-#[test]
-fn record_patterns_2() {
-    let source = r#"
-type Ara = Kueh { a: Int, b: String } | Morbuk
-
-let alpha = Ara::Kueh { a: 10, b: "sanchez" }
-if alpha {
-    is Ara::Kueh { a, b: le_value } then (le_value, (a*2))
-    is _ then ("nooo", 8888)
-}"#;
-    eval_assert(source, r#"("sanchez", 20)"#);
-}
-
-#[test]
-fn record_patterns_3() {
-    let source = r#"
-type Vstsavlobs = { tkveni: Int, b: Ia }
-type Ia = { sitqva: Int, ghmerts: String }
-let b = Vstsavlobs { tkveni: 3, b: Ia::Ia { sitqva: 5, ghmerts: "ooo" } }
-if b {
-    is Vstsavlobs::Vstsavlobs { tkveni: _, b: Ia::Ia { sitqva, ghmerts } } then sitqva
-    is _ then 5000
-}"#;
-    eval_assert(source, "5");
-}
-
-#[test]
-fn if_is_patterns() {
-    let source = r#"
-type Option<T> = Some(T) | None
-let q = "a string"
-let x = Option::Some(9); if x is Option::Some(q) then { q } else { 0 }"#;
-
-    eval_assert(source, "9");
-
-    let source = r#"
-type Option<T> = Some(T) | None
-let q = "a string"
-let outer = 2
-let x = Option::None; if x is Option::Some(q) then { q } else { -2 + outer }"#;
-    eval_assert(source, "0");
-}
-
-#[test]
-fn full_if_matching() {
-    let source = r#"
-type Option<T> = Some(T) | None
-let a = Option::None
-if a { is Option::None then 4; is Option::Some(x) then x }
-    "#;
-    eval_assert(source, "4");
-
-    let source = r#"
-type Option<T> = Some(T) | None
-let sara = Option::Some(99)
-if sara { is Option::None then 1 + 3; is Option::Some(x) then x }
-    "#;
-    eval_assert(source, "99");
-
-    let source = r#"
-let a = 10
-if a { is 10 then "x"; is 4 then "y" }
-    "#;
-    eval_assert(source, "\"x\"");
-
-    let source = r#"
-let a = 10
-if a { is 15 then "x"; is 10 then "y" }
-    "#;
-    eval_assert(source, "\"y\"");
-}
-
-//TODO - I can probably cut down some of these
-#[test]
-fn string_pattern() {
-    let source = r#"
-let a = "foo"
-if a { is "foo" then "x"; is _ then "y" }
-    "#;
-    eval_assert(source, "\"x\"");
-}
-
-#[test]
-fn boolean_pattern() {
-    let source = r#"
-let a = true
-if a {
-  is true then "x"
-  is false then "y"
-}
-"#;
-    eval_assert(source, "\"x\"");
-}
-
-#[test]
-fn boolean_pattern_2() {
-    let source = r#"
-let a = false
-if a { is true then "x"; is false then "y" }
-"#;
-    eval_assert(source, "\"y\"");
-}
-
-#[test]
-fn ignore_pattern() {
-    let source = r#"
-type Option<T> = Some(T) | None
-if Option::Some(10) {
-  is _ then "hella"
-}
-"#;
-    eval_assert(source, "\"hella\"");
-}
-
-#[test]
-fn tuple_pattern() {
-    let source = r#"
-if (1, 2) {
-  is (1, x) then x;
-  is _ then 99
-}
-"#;
-    eval_assert(source, "2");
-}
-
-#[test]
-fn tuple_pattern_2() {
-    let source = r#"
-if (1, 2) {
-  is (10, x) then x
-  is (y, x) then x + y
-}
-"#;
-    eval_assert(source, "3");
-}
-
-#[test]
-fn tuple_pattern_3() {
-    let source = r#"
-if (1, 5) {
-  is (10, x) then x
-  is (1, x) then x
-}
-"#;
-    eval_assert(source, "5");
-}
-
-#[test]
-fn tuple_pattern_4() {
-    let source = r#"
-if (1, 5) {
-  is (10, x) then x
-  is (1, x) then x
-}
-"#;
-    eval_assert(source, "5");
-}
-
-#[test]
-fn prim_obj_pattern() {
-    let source = r#"
-type Stuff = Mulch(Nat) | Jugs(Nat, String) | Mardok
-let a = Stuff::Mulch(20)
-let b = Stuff::Jugs(1, "haha")
-let c = Stuff::Mardok
-
-let x = if a {
-  is Stuff::Mulch(20) then "x"
-  is _ then "ERR"
-}
-
-let y = if b {
-  is Stuff::Mulch(n) then "ERR"
-  is Stuff::Jugs(2, _) then "ERR"
-  is Stuff::Jugs(1, s) then s
-  is _ then "ERR"
-}
-
-let z = if c {
-  is Stuff::Jugs(_, _) then "ERR"
-  is Stuff::Mardok then "NIGH"
-  is _ then "ERR"
-}
-
-(x, y, z)
-"#;
-    eval_assert(source, r#"("x", "haha", "NIGH")"#);
-}
-
-#[test]
-fn basic_lambda_evaluation_1() {
-    let source = r#"
-let q = \(x, y) { x * y }
-let x = q(5, 2)
-let y = \(m, n, o) { m + n + o }(1,2,3)
-(x, y)
-"#;
-
-    eval_assert(source, r"(10, 6)");
-}
-
-#[test]
-fn basic_lambda_evaluation_2() {
-    let source = r#"
-fn milta() {
-  \(x) { x + 33 }
-}
-milta()(10)
-  "#;
-
-    eval_assert(source, "43");
-}
-
-#[test]
-fn import_all() {
-    let source = r#"
-type Option<T> = Some(T) | None
-import Option::*
-let x = Some(9); if x is Some(q) then { q } else { 0 }"#;
-    eval_assert(source, "9");
-}
-
-#[test]
-fn accessors() {
-    let source = r#"
-type Klewos = { a: Int, b: String }
-let value = Klewos::Klewos { a: 50, b: "nah" }
-(value.a, value.b)
-    "#;
-
-    eval_assert(source, r#"(50, "nah")"#);
-}
-
-#[test]
-fn early_return() {
-    let source = r#"
-fn chnurmek(a: Int): Int {
-    if a == 5 then {
-        return 9999;
-    }
-    return (a + 2);
-}
-
-(chnurmek(5), chnurmek(0))
-    "#;
-    eval_assert(source, r#"(9999, 2)"#);
-
-    let source = r#"
-fn marbuk(a: Int, b: Int): (Int, Int) {
-   if a == 5 then {
-        if b == 6 then {
-            return (50, 50);
-        }
-
-        return (a, b + 1)
-   }
-   (a * 100, b * 100)
-}
-
-let x = marbuk(1, 1)
-let y = marbuk(5, 1)
-let z = marbuk(5, 6)
-
-(x, y, z)
-    "#;
-    eval_assert(source, "((100, 100), (5, 2), (50, 50))");
-}
-
-#[test]
-fn loops() {
-    let source = r#"
-let mut a = 0
-let mut count = 0
-while a != 5 {
-    a = a + 1
-    count = count + 100
-}
-
-count
-    "#;
-    eval_assert(source, "500");
-}
-
-#[test]
-fn loops_2() {
-    let source = r#"
-let mut a = 0
-let mut acc = 0
-while a < 10 {
-    acc = acc + 1
-    a = a + 1
-
-    // Without this continue, the output would be 20
-    if a == 5 then {
-        continue
-    }
-
-    acc = acc + 1
-}
-
-acc"#;
-    eval_assert(source, "19");
-}
-
-#[test]
-fn list_literals() {
-    eval_assert(
-        r#"
-let a = [7, 8, 9]
-a
-"#,
-        "[7, 8, 9]",
-    );
-
-    eval_assert(
-        r#"
-let a = [7, 8, 9]
-fn foo() { return 2 }
-(a[0], a[foo()])
-"#,
-        "(7, 9)",
-    );
-}
-
-#[test]
-fn eval_method() {
-    let src = r#"
-type Thing = Thing
-impl Thing {
-    fn a_method() {
-        20
-    }
-
-}
-
-let a = Thing::Thing
-4 + a.a_method()
-    "#;
-    eval_assert(src, "24");
-}

schala-lang/src/type_inference/mod.rs

@@ -1,227 +0,0 @@
-use std::{collections::HashMap, convert::From};
-
-use crate::{
-    ast::{TypeIdentifier, AST},
-    identifier::{define_id_kind, Id, IdStore},
-};
-
-define_id_kind!(TypeItem);
-pub type TypeId = Id<TypeItem>;
-
-pub struct TypeContext {
-    defined_types: HashMap<TypeId, DefinedType>,
-    type_id_store: IdStore<TypeItem>,
-}
-
-impl TypeContext {
-    pub fn new() -> Self {
-        Self { defined_types: HashMap::new(), type_id_store: IdStore::new() }
-    }
-
-    pub fn register_type(&mut self, builder: TypeBuilder) -> TypeId {
-        let type_id = self.type_id_store.fresh();
-
-        let mut pending_variants = vec![];
-        for variant_builder in builder.variants.into_iter() {
-            let members = variant_builder.members;
-            if members.is_empty() {
-                pending_variants.push(Variant { name: variant_builder.name, members: VariantMembers::Unit });
-                continue;
-            }
-            let record_variant = matches!(members.get(0).unwrap(), VariantMemberBuilder::KeyVal(..));
-
-            if record_variant {
-                let pending_members = members.into_iter().map(|var| match var {
-                    VariantMemberBuilder::KeyVal(name, ty) => (name, ty),
-                    _ => panic!("Compiler internal error: variant mismatch"),
-                });
-
-                //TODO make this mapping meaningful
-                let type_ids = pending_members
-                    .into_iter()
-                    .map(|(name, _ty_id)| (name, self.type_id_store.fresh()))
-                    .collect();
-                pending_variants
-                    .push(Variant { name: variant_builder.name, members: VariantMembers::Record(type_ids) });
-            } else {
-                let pending_members = members.into_iter().map(|var| match var {
-                    VariantMemberBuilder::Pending(pending_type) => pending_type,
-                    _ => panic!("Compiler internal error: variant mismatch"),
-                });
-
-                //TODO make this mapping meaningful
-                let type_ids = pending_members.into_iter().map(|_ty_id| self.type_id_store.fresh()).collect();
-
-                pending_variants
-                    .push(Variant { name: variant_builder.name, members: VariantMembers::Tuple(type_ids) });
-            }
-        }
-
-        // Eventually, I will want to have a better way of determining which numeric tag goes with
-        // which variant. For now, just sort them alphabetically.
-        pending_variants.sort_unstable_by(|a, b| a.name.cmp(&b.name));
-
-        let defined = DefinedType { name: builder.name, variants: pending_variants };
-
-        self.defined_types.insert(type_id, defined);
-        type_id
-    }
-
-    pub fn variant_local_name(&self, type_id: &TypeId, tag: u32) -> Option<&str> {
-        self.defined_types
-            .get(type_id)
-            .and_then(|defined| defined.variants.get(tag as usize))
-            .map(|variant| variant.name.as_ref())
-    }
-
-    pub fn lookup_variant_arity(&self, type_id: &TypeId, tag: u32) -> Option<u32> {
-        self.defined_types.get(type_id).and_then(|defined| defined.variants.get(tag as usize)).map(
-            |variant| match &variant.members {
-                VariantMembers::Unit => 0,
-                VariantMembers::Tuple(items) => items.len() as u32,
-                VariantMembers::Record(items) => items.len() as u32,
-            },
-        )
-    }
-
-    pub fn lookup_record_members(&self, type_id: &TypeId, tag: u32) -> Option<&[(String, TypeId)]> {
-        self.defined_types.get(type_id).and_then(|defined| defined.variants.get(tag as usize)).and_then(
-            |variant| match &variant.members {
-                VariantMembers::Record(items) => Some(items.as_ref()),
-                _ => None,
-            },
-        )
-    }
-
-    pub fn lookup_type(&self, type_id: &TypeId) -> Option<&DefinedType> {
-        self.defined_types.get(type_id)
-    }
-
-    //TODO return some kind of overall type later?
-    pub fn typecheck(&mut self, ast: &AST) -> Result<(), TypeError> {
-        Ok(())
-    }
-}
-
-/// A type defined in program source code, as opposed to a builtin.
-#[allow(dead_code)]
-#[derive(Debug)]
-pub struct DefinedType {
-    pub name: String,
-
-    // the variants are in this list according to tag order
-    pub variants: Vec<Variant>,
-}
-
-#[derive(Debug)]
-pub struct Variant {
-    pub name: String,
-    pub members: VariantMembers,
-}
-
-#[derive(Debug)]
-pub enum VariantMembers {
-    Unit,
-    // Should be non-empty
-    Tuple(Vec<TypeId>),
-    Record(Vec<(String, TypeId)>),
-}
-
-/// Represents a type mentioned as a member of another type during the type registration process.
-/// It may not have been registered itself in the relevant context.
-#[allow(dead_code)]
-#[derive(Debug)]
-pub struct PendingType {
-    inner: TypeIdentifier,
-}
-
-impl From<&TypeIdentifier> for PendingType {
-    fn from(type_identifier: &TypeIdentifier) -> Self {
-        Self { inner: type_identifier.clone() }
-    }
-}
-
-#[derive(Debug)]
-pub struct TypeBuilder {
-    name: String,
-    variants: Vec<VariantBuilder>,
-}
-
-impl TypeBuilder {
-    pub fn new(name: &str) -> Self {
-        Self { name: name.to_string(), variants: vec![] }
-    }
-
-    pub fn add_variant(&mut self, vb: VariantBuilder) {
-        self.variants.push(vb);
-    }
-}
-
-#[derive(Debug)]
-pub struct VariantBuilder {
-    name: String,
-    members: Vec<VariantMemberBuilder>,
-}
-
-impl VariantBuilder {
-    pub fn new(name: &str) -> Self {
-        Self { name: name.to_string(), members: vec![] }
-    }
-
-    pub fn add_member(&mut self, member_ty: PendingType) {
-        self.members.push(VariantMemberBuilder::Pending(member_ty));
-    }
-
-    // You can't call this and `add_member` on the same fn, there should be a runtime error when
-    // that's detected.
-    pub fn add_record_member(&mut self, name: &str, ty: PendingType) {
-        self.members.push(VariantMemberBuilder::KeyVal(name.to_string(), ty));
-    }
-}
-
-#[derive(Debug)]
-enum VariantMemberBuilder {
-    Pending(PendingType),
-    KeyVal(String, PendingType),
-}
-
-#[derive(Debug, Clone)]
-pub struct TypeError {
-    pub msg: String,
-}
-
-#[allow(dead_code)]
-#[derive(Debug, Clone, PartialEq, Eq)]
-pub enum TypeConst {
-    Unit,
-    Nat,
-    Int,
-    Float,
-    StringT,
-    Bool,
-    Ordering,
-}
-
-#[allow(dead_code)]
-#[derive(Debug, Clone, PartialEq)]
-pub enum Type {
-    Const(TypeConst),
-    //Var(TypeVar),
-    Arrow { params: Vec<Type>, ret: Box<Type> },
-    Compound { ty_name: String, args: Vec<Type> },
-}
-
-macro_rules! ty {
-    ($type_name:ident) => {
-        Type::Const(crate::type_inference::TypeConst::$type_name)
-    };
-    ($t1:ident -> $t2:ident) => {
-        Type::Arrow { params: vec![ty!($t1)], ret: Box::new(ty!($t2)) }
-    };
-    ($t1:ident -> $t2:ident -> $t3:ident) => {
-        Type::Arrow { params: vec![ty!($t1), ty!($t2)], ret: Box::new(ty!($t3)) }
-    };
-    ($type_list:ident, $ret_type:ident) => {
-        Type::Arrow { params: $type_list, ret: Box::new($ret_type) }
-    };
-}

schala-lang/src/util.rs

@@ -1,85 +0,0 @@
-use std::{cmp::Eq, collections::HashMap, fmt::Write, hash::Hash};
-
-/// Utility function for printing a comma-delimited list of things
-pub(crate) fn delim_wrapped(lhs: char, rhs: char, terms: impl Iterator<Item = String>) -> String {
-    let mut buf = String::new();
-    write!(buf, "{}", lhs).unwrap();
-    for term in terms.map(Some).intersperse(None) {
-        match term {
-            Some(e) => write!(buf, "{}", e).unwrap(),
-            None => write!(buf, ", ").unwrap(),
-        };
-    }
-    write!(buf, "{}", rhs).unwrap();
-    buf
-}
-
-#[derive(Default, Debug)]
-pub struct ScopeStack<'a, T: 'a, V: 'a, N = String>
-where T: Hash + Eq
-{
-    parent: Option<&'a ScopeStack<'a, T, V, N>>,
-    values: HashMap<T, V>,
-    scope_name: Option<N>,
-}
-
-impl<'a, T, V, N> ScopeStack<'a, T, V, N>
-where T: Hash + Eq
-{
-    pub fn new(scope_name: Option<N>) -> Self
-    where T: Hash + Eq {
-        ScopeStack { parent: None, values: HashMap::new(), scope_name }
-    }
-    pub fn insert(&mut self, key: T, value: V)
-    where T: Hash + Eq {
-        self.values.insert(key, value);
-    }
-    pub fn lookup(&self, key: &T) -> Option<&V>
-    where T: Hash + Eq {
-        match (self.values.get(key), self.parent) {
-            (None, None) => None,
-            (None, Some(parent)) => parent.lookup(key),
-            (Some(value), _) => Some(value),
-        }
-    }
-
-    pub fn new_scope(&'a self, scope_name: Option<N>) -> Self
-    where T: Hash + Eq {
-        ScopeStack { parent: Some(self), values: HashMap::default(), scope_name }
-    }
-
-    #[allow(dead_code)]
-    pub fn lookup_with_scope(&self, key: &T) -> Option<(&V, Option<&N>)>
-    where T: Hash + Eq {
-        match (self.values.get(key), self.parent) {
-            (None, None) => None,
-            (None, Some(parent)) => parent.lookup_with_scope(key),
-            (Some(value), _) => Some((value, self.scope_name.as_ref())),
-        }
-    }
-
-    pub fn get_name(&self) -> Option<&N> {
-        self.scope_name.as_ref()
-    }
-}
-
-/// Quickly create an AST from a string, with no error checking. For test use only
-#[cfg(test)]
-pub fn quick_ast(input: &str) -> crate::ast::AST {
-    let mut parser = crate::parsing::Parser::new();
-    let output = parser.parse(input);
-    match output {
-        Ok(output) => output,
-        Err(err) => {
-            println!("Parse error: {}", err.msg);
-            panic!();
-        }
-    }
-}
-
-#[allow(unused_macros)]
-macro_rules! rc {
-    ($string:tt) => {
-        Rc::new(stringify!($string).to_string())
-    };
-}

schala-repl/Cargo.toml

@@ -2,21 +2,22 @@
 name = "schala-repl"
 version = "0.1.0"
 authors = ["greg <greg.shuflin@protonmail.com>"]
-edition = "2021"
+edition = "2018"
 
 [dependencies]
 llvm-sys = "70.0.2"
 take_mut = "0.2.2"
-itertools = "0.10"
+itertools = "0.5.8"
+getopts = "0.2.18"
 lazy_static = "0.2.8"
 maplit = "*"
-colored = "1.8"
-serde = "1.0"
-serde_derive = "1.0"
-serde_json = "1.0"
+colored = "1.7"
+serde = "1.0.91"
+serde_derive = "1.0.91"
+serde_json = "1.0.15"
 phf = "0.7.12"
 includedir = "0.2.0"
-linefeed = "0.6.0"
+linefeed = "0.5.0"
 regex = "0.2"
 
 [build-dependencies]

schala-repl/build.rs

@@ -3,5 +3,8 @@ extern crate includedir_codegen;
 use includedir_codegen::Compression;
 
 fn main() {
-    includedir_codegen::start("WEBFILES").dir("../static", Compression::Gzip).build("static.rs").unwrap();
+    includedir_codegen::start("WEBFILES")
+        .dir("../static", Compression::Gzip)
+        .build("static.rs")
+        .unwrap();
 }

schala-repl/src/command_tree.rs

@@ -1,116 +0,0 @@
-use colored::*;
-
-use crate::{
-    directive_actions::DirectiveAction, language::ProgrammingLanguageInterface, InterpreterDirectiveOutput,
-    Repl,
-};
-
-/// A CommandTree is either a `Terminal` or a `NonTerminal`. When command parsing reaches the first
-/// Terminal, it will use the `DirectiveAction` found there to find an appropriate function to execute,
-/// and then execute it with any remaining arguments
-#[derive(Clone)]
-pub enum CommandTree {
-    Terminal {
-        name: String,
-        children: Vec<CommandTree>,
-        help_msg: Option<String>,
-        action: DirectiveAction,
-    },
-    NonTerminal {
-        name: String,
-        children: Vec<CommandTree>,
-        help_msg: Option<String>,
-        action: DirectiveAction,
-    },
-    Top(Vec<CommandTree>),
-}
-
-impl CommandTree {
-    pub fn nonterm_no_further_tab_completions(s: &str, help: Option<&str>) -> CommandTree {
-        CommandTree::NonTerminal {
-            name: s.to_string(),
-            help_msg: help.map(|x| x.to_string()),
-            children: vec![],
-            action: DirectiveAction::Null,
-        }
-    }
-
-    pub fn terminal(
-        s: &str,
-        help: Option<&str>,
-        children: Vec<CommandTree>,
-        action: DirectiveAction,
-    ) -> CommandTree {
-        CommandTree::Terminal { name: s.to_string(), help_msg: help.map(|x| x.to_string()), children, action }
-    }
-
-    pub fn nonterm(s: &str, help: Option<&str>, children: Vec<CommandTree>) -> CommandTree {
-        CommandTree::NonTerminal {
-            name: s.to_string(),
-            help_msg: help.map(|x| x.to_string()),
-            children,
-            action: DirectiveAction::Null,
-        }
-    }
-
-    pub fn get_cmd(&self) -> &str {
-        match self {
-            CommandTree::Terminal { name, .. } => name.as_str(),
-            CommandTree::NonTerminal { name, .. } => name.as_str(),
-            CommandTree::Top(_) => "",
-        }
-    }
-    pub fn get_help(&self) -> &str {
-        match self {
-            CommandTree::Terminal { help_msg, .. } =>
-                help_msg.as_ref().map(|s| s.as_str()).unwrap_or("<no help text provided>"),
-            CommandTree::NonTerminal { help_msg, .. } =>
-                help_msg.as_ref().map(|s| s.as_str()).unwrap_or("<no help text provided>"),
-            CommandTree::Top(_) => "",
-        }
-    }
-    pub fn get_children(&self) -> &Vec<CommandTree> {
-        use CommandTree::*;
-        match self {
-            Terminal { children, .. } | NonTerminal { children, .. } | Top(children) => children,
-        }
-    }
-    pub fn get_subcommands(&self) -> Vec<&str> {
-        self.get_children().iter().map(|x| x.get_cmd()).collect()
-    }
-
-    pub fn perform<L: ProgrammingLanguageInterface>(
-        &self,
-        repl: &mut Repl<L>,
-        arguments: &[&str],
-    ) -> InterpreterDirectiveOutput {
-        let mut dir_pointer: &CommandTree = self;
-        let mut idx = 0;
-
-        let res: Result<(DirectiveAction, usize), String> = loop {
-            match dir_pointer {
-                CommandTree::Top(subcommands) | CommandTree::NonTerminal { children: subcommands, .. } => {
-                    let next_command = match arguments.get(idx) {
-                        Some(cmd) => cmd,
-                        None => break Err("Command requires arguments".to_owned()),
-                    };
-                    idx += 1;
-                    match subcommands.iter().find(|sc| sc.get_cmd() == *next_command) {
-                        Some(command_tree) => {
-                            dir_pointer = command_tree;
-                        }
-                        None => break Err(format!("Command {} not found", next_command)),
-                    };
-                }
-                CommandTree::Terminal { action, .. } => {
-                    break Ok((action.clone(), idx));
-                }
-            }
-        };
-
-        match res {
-            Ok((action, idx)) => action.perform(repl, &arguments[idx..]),
-            Err(err) => Some(err.red().to_string()),
-        }
-    }
-}

schala-repl/src/directive_actions.rs

@@ -1,77 +0,0 @@
-use std::fmt::Write as FmtWrite;
-
-use crate::{
-    help::help,
-    language::{LangMetaRequest, LangMetaResponse, ProgrammingLanguageInterface},
-    InterpreterDirectiveOutput, Repl,
-};
-
-#[derive(Debug, Clone)]
-pub enum DirectiveAction {
-    Null,
-    Help,
-    QuitProgram,
-    ListPasses,
-    TotalTime(bool),
-    StageTime(bool),
-    Doc,
-}
-
-impl DirectiveAction {
-    pub fn perform<L: ProgrammingLanguageInterface>(
-        &self,
-        repl: &mut Repl<L>,
-        arguments: &[&str],
-    ) -> InterpreterDirectiveOutput {
-        use DirectiveAction::*;
-        match self {
-            Null => None,
-            Help => help(repl, arguments),
-            QuitProgram => {
-                repl.save_before_exit();
-                ::std::process::exit(0)
-            }
-            ListPasses => {
-                let pass_names = match repl.language_state.request_meta(LangMetaRequest::StageNames) {
-                    LangMetaResponse::StageNames(names) => names,
-                    _ => vec![],
-                };
-
-                let mut buf = String::new();
-                for pass in pass_names.iter().map(Some).intersperse(None) {
-                    match pass {
-                        Some(pass) => write!(buf, "{}", pass).unwrap(),
-                        None => write!(buf, " -> ").unwrap(),
-                    }
-                }
-                Some(buf)
-            }
-            TotalTime(value) => {
-                repl.options.show_total_time = *value;
-                None
-            }
-            StageTime(value) => {
-                repl.options.show_stage_times = *value;
-                None
-            }
-            Doc => doc(repl, arguments),
-        }
-    }
-}
-
-fn doc<L: ProgrammingLanguageInterface>(
-    repl: &mut Repl<L>,
-    arguments: &[&str],
-) -> InterpreterDirectiveOutput {
-    arguments
-        .get(0)
-        .map(|cmd| {
-            let source = cmd.to_string();
-            let meta = LangMetaRequest::Docs { source };
-            match repl.language_state.request_meta(meta) {
-                LangMetaResponse::Docs { doc_string } => Some(doc_string),
-                _ => Some("Invalid doc response".to_owned()),
-            }
-        })
-        .unwrap_or_else(|| Some(":docs needs an argument".to_owned()))
-}

schala-repl/src/directives.rs

@@ -1,68 +0,0 @@
-use crate::{command_tree::CommandTree, directive_actions::DirectiveAction};
-
-pub fn directives_from_pass_names(pass_names: &[String]) -> CommandTree {
-    let passes_directives: Vec<CommandTree> = pass_names
-        .iter()
-        .map(|pass_name| {
-            if pass_name == "parsing" {
-                CommandTree::nonterm(
-                    pass_name,
-                    None,
-                    vec![
-                        CommandTree::nonterm_no_further_tab_completions("compact", None),
-                        CommandTree::nonterm_no_further_tab_completions("expanded", None),
-                        CommandTree::nonterm_no_further_tab_completions("trace", None),
-                    ],
-                )
-            } else {
-                CommandTree::nonterm_no_further_tab_completions(pass_name, None)
-            }
-        })
-        .collect();
-    CommandTree::Top(get_list(&passes_directives, true))
-}
-
-fn get_list(passes_directives: &[CommandTree], include_help: bool) -> Vec<CommandTree> {
-    use DirectiveAction::*;
-
-    vec![
-        CommandTree::terminal("exit", Some("exit the REPL"), vec![], QuitProgram),
-        //TODO there should be an alias for this
-        CommandTree::terminal("quit", Some("exit the REPL"), vec![], QuitProgram),
-        CommandTree::terminal(
-            "help",
-            Some("Print this help message"),
-            if include_help { get_list(passes_directives, false) } else { vec![] },
-            Help,
-        ),
-        CommandTree::nonterm(
-            "debug",
-            Some("Configure debug information"),
-            vec![
-                CommandTree::terminal(
-                    "list-passes",
-                    Some("List all registered compiler passes"),
-                    vec![],
-                    ListPasses,
-                ),
-                CommandTree::nonterm(
-                    "total-time",
-                    None,
-                    vec![
-                        CommandTree::terminal("on", None, vec![], TotalTime(true)),
-                        CommandTree::terminal("off", None, vec![], TotalTime(false)),
-                    ],
-                ),
-                CommandTree::nonterm(
-                    "stage-times",
-                    Some("Computation time per-stage"),
-                    vec![
-                        CommandTree::terminal("on", None, vec![], StageTime(true)),
-                        CommandTree::terminal("off", None, vec![], StageTime(false)),
-                    ],
-                ),
-            ],
-        ),
-        CommandTree::terminal("doc", Some("Get language-specific help for an item"), vec![], Doc),
-    ]
-}

schala-repl/src/help.rs

@@ -1,63 +0,0 @@
-use std::fmt::Write as FmtWrite;
-
-use colored::*;
-
-use crate::{
-    command_tree::CommandTree, language::ProgrammingLanguageInterface, InterpreterDirectiveOutput, Repl,
-};
-
-pub fn help<L: ProgrammingLanguageInterface>(
-    repl: &mut Repl<L>,
-    arguments: &[&str],
-) -> InterpreterDirectiveOutput {
-    match arguments {
-        [] => global_help(repl),
-        commands => {
-            let dirs = repl.get_directives();
-            Some(match get_directive_from_commands(commands, &dirs) {
-                None => format!("Directive `{}` not found", commands.last().unwrap()),
-                Some(dir) => {
-                    let mut buf = String::new();
-                    let cmd = dir.get_cmd();
-                    let children = dir.get_children();
-                    writeln!(buf, "`{}` - {}", cmd, dir.get_help()).unwrap();
-                    for sub in children.iter() {
-                        writeln!(buf, "\t`{} {}` - {}", cmd, sub.get_cmd(), sub.get_help()).unwrap();
-                    }
-                    buf
-                }
-            })
-        }
-    }
-}
-
-fn get_directive_from_commands<'a>(commands: &[&str], dirs: &'a CommandTree) -> Option<&'a CommandTree> {
-    let mut directive_list = dirs.get_children();
-    let mut matched_directive = None;
-    for cmd in commands {
-        let found = directive_list.iter().find(|directive| directive.get_cmd() == *cmd);
-        if let Some(dir) = found {
-            directive_list = dir.get_children();
-        }
-
-        matched_directive = found;
-    }
-    matched_directive
-}
-
-fn global_help<L: ProgrammingLanguageInterface>(repl: &mut Repl<L>) -> InterpreterDirectiveOutput {
-    let mut buf = String::new();
-
-    writeln!(buf, "{} version {}", "Schala REPL".bright_red().bold(), crate::VERSION_STRING).unwrap();
-    writeln!(buf, "-----------------------").unwrap();
-
-    for directive in repl.get_directives().get_children() {
-        writeln!(buf, "{}{} - {}", repl.sigil, directive.get_cmd(), directive.get_help()).unwrap();
-    }
-
-    writeln!(buf).unwrap();
-    writeln!(buf, "Language-specific help for {}", <L as ProgrammingLanguageInterface>::language_name())
-        .unwrap();
-    writeln!(buf, "-----------------------").unwrap();
-    Some(buf)
-}

schala-repl/src/language.rs

@@ -1,56 +1,71 @@
-use std::{collections::HashSet, time};
+use std::time;
+use std::collections::HashSet;
 
 pub trait ProgrammingLanguageInterface {
-    type Config: Default + Clone;
-    fn language_name() -> String;
-    fn source_file_suffix() -> String;
+  fn get_language_name(&self) -> String;
+  fn get_source_file_suffix(&self) -> String;
 
-    fn run_computation(&mut self, _request: ComputationRequest<Self::Config>) -> ComputationResponse;
-
-    fn request_meta(&mut self, _request: LangMetaRequest) -> LangMetaResponse {
-        LangMetaResponse::Custom { kind: "not-implemented".to_owned(), value: format!("") }
+  fn run_computation(&mut self, _request: ComputationRequest) -> ComputationResponse {
+    ComputationResponse {
+      main_output: Err(format!("Computation pipeline not implemented")),
+      global_output_stats: GlobalOutputStats::default(),
+      debug_responses: vec![],
     }
+  }
+
+  fn request_meta(&mut self, _request: LangMetaRequest) -> LangMetaResponse {
+    LangMetaResponse::Custom { kind: format!("not-implemented"), value: format!("") }
+  }
 }
 
-pub struct ComputationRequest<'a, T> {
-    pub source: &'a str,
-    pub config: T,
-    pub debug_requests: HashSet<DebugAsk>,
+pub struct ComputationRequest<'a> {
+  pub source: &'a str,
+  pub debug_requests: HashSet<DebugAsk>,
 }
 
 pub struct ComputationResponse {
-    pub main_output: Result<String, String>,
-    pub global_output_stats: GlobalOutputStats,
-    pub debug_responses: Vec<DebugResponse>,
+  pub main_output: Result<String, String>,
+  pub global_output_stats: GlobalOutputStats,
+  pub debug_responses: Vec<DebugResponse>,
 }
 
 #[derive(Default, Debug)]
 pub struct GlobalOutputStats {
-    pub total_duration: time::Duration,
-    pub stage_durations: Vec<(String, time::Duration)>,
+  pub total_duration: time::Duration,
+  pub stage_durations: Vec<(String, time::Duration)>
 }
 
 #[derive(Debug, Clone, Hash, Eq, PartialEq, Deserialize, Serialize)]
 pub enum DebugAsk {
-    Timing,
-    ByStage { stage_name: String, token: Option<String> },
+  Timing,
+  ByStage { stage_name: String },
 }
 
 pub struct DebugResponse {
-    pub ask: DebugAsk,
-    pub value: String,
+  pub ask: DebugAsk,
+  pub value: String
 }
 
 pub enum LangMetaRequest {
-    StageNames,
-    Docs { source: String },
-    Custom { kind: String, value: String },
-    ImmediateDebug(DebugAsk),
+  StageNames,
+  Docs {
+    source: String,
+  },
+  Custom {
+    kind: String,
+    value: String
+  },
+  ImmediateDebug(DebugAsk),
 }
 
 pub enum LangMetaResponse {
-    StageNames(Vec<String>),
-    Docs { doc_string: String },
-    Custom { kind: String, value: String },
-    ImmediateDebug(DebugResponse),
+  StageNames(Vec<String>),
+  Docs {
+    doc_string: String,
+  },
+  Custom {
+    kind: String,
+    value: String
+  },
+  ImmediateDebug(DebugResponse),
 }

schala-repl/src/lib.rs

@@ -1,249 +1,92 @@
-#![feature(box_patterns, proc_macro_hygiene, decl_macro, iter_intersperse)]
+#![feature(link_args)]
+#![feature(slice_patterns, box_patterns, box_syntax, proc_macro_hygiene, decl_macro)]
+#![feature(plugin)]
+extern crate getopts;
+extern crate linefeed;
+extern crate itertools;
+extern crate colored;
 
 #[macro_use]
 extern crate serde_derive;
+extern crate serde_json;
 extern crate includedir;
 extern crate phf;
-extern crate serde_json;
 
-mod command_tree;
+use std::collections::HashSet;
+use std::path::Path;
+use std::fs::File;
+use std::io::Read;
+use std::process::exit;
+
+mod repl;
 mod language;
-use self::command_tree::CommandTree;
-mod repl_options;
-use repl_options::ReplOptions;
-mod directive_actions;
-mod directives;
-use directives::directives_from_pass_names;
-mod help;
-mod response;
-use std::{collections::HashSet, sync::Arc};
 
-use colored::*;
-pub use language::{
-    ComputationRequest, ComputationResponse, DebugAsk, DebugResponse, GlobalOutputStats, LangMetaRequest,
-    LangMetaResponse, ProgrammingLanguageInterface,
-};
-use response::ReplResponse;
+pub use language::{ProgrammingLanguageInterface,
+ComputationRequest, ComputationResponse,
+LangMetaRequest, LangMetaResponse,
+DebugResponse, DebugAsk, GlobalOutputStats};
 
 include!(concat!(env!("OUT_DIR"), "/static.rs"));
-const VERSION_STRING: &str = "0.1.0";
+const VERSION_STRING: &'static str = "0.1.0";
 
-const HISTORY_SAVE_FILE: &str = ".schala_history";
-const OPTIONS_SAVE_FILE: &str = ".schala_repl";
+pub fn start_repl(langs: Vec<Box<dyn ProgrammingLanguageInterface>>) {
+  let options = command_line_options().parse(std::env::args()).unwrap_or_else(|e| {
+    println!("{:?}", e);
+    exit(1);
+  });
 
-type InterpreterDirectiveOutput = Option<String>;
+  if options.opt_present("help") {
+    println!("{}", command_line_options().usage("Schala metainterpreter"));
+    exit(0);
+  }
 
-pub struct Repl<L: ProgrammingLanguageInterface> {
-    /// If this is the first character typed by a user into the repl, the following
-    /// will be interpreted as a directive to the REPL rather than a command in the
-    /// running programming language.
-    sigil: char,
-    line_reader: ::linefeed::interface::Interface<::linefeed::terminal::DefaultTerminal>,
-    language_state: L,
-    options: ReplOptions,
+  match options.free[..] {
+    [] | [_] => {
+      let mut repl = repl::Repl::new(langs);
+      repl.run_repl();
+    }
+    [_, ref filename, _..] => {
+      run_noninteractive(filename, langs);
+    }
+  };
 }
 
-#[derive(Clone)]
-enum PromptStyle {
-    Normal,
-    Multiline,
+fn run_noninteractive(filename: &str, languages: Vec<Box<ProgrammingLanguageInterface>>) {
+  let path = Path::new(filename);
+  let ext = path.extension().and_then(|e| e.to_str()).unwrap_or_else(|| {
+    println!("Source file lacks extension");
+    exit(1);
+  });
+  let mut language = Box::new(languages.into_iter().find(|lang| lang.get_source_file_suffix() == ext)
+    .unwrap_or_else(|| {
+      println!("Extension .{} not recognized", ext);
+      exit(1);
+    }));
+
+  let mut source_file = File::open(path).unwrap();
+  let mut buffer = String::new();
+  source_file.read_to_string(&mut buffer).unwrap();
+
+  let request = ComputationRequest {
+    source: &buffer,
+    debug_requests: HashSet::new(),
+  };
+
+  let response = language.run_computation(request);
+  match response.main_output {
+    Ok(s) => println!("{}", s),
+    Err(s) => println!("{}", s)
+  };
 }
 
-impl<L: ProgrammingLanguageInterface> Repl<L> {
-    pub fn new(initial_state: L) -> Self {
-        use linefeed::Interface;
-        let line_reader = Interface::new("schala-repl").unwrap();
-        let sigil = ':';
 
-        Repl { sigil, line_reader, language_state: initial_state, options: ReplOptions::new() }
-    }
-
-    pub fn run_repl(&mut self, config: L::Config) {
-        println!("Schala meta-interpeter version {}", VERSION_STRING);
-        println!("Type {} for help with the REPL", format!("{}help", self.sigil).bright_green().bold());
-        self.load_options();
-        self.handle_repl_loop(config);
-        self.save_before_exit();
-        println!("Exiting...");
-    }
-
-    fn load_options(&mut self) {
-        self.line_reader.load_history(HISTORY_SAVE_FILE).unwrap_or(());
-        match ReplOptions::load_from_file(OPTIONS_SAVE_FILE) {
-            Ok(options) => {
-                self.options = options;
-            }
-            Err(e) => eprintln!("{}", e),
-        }
-    }
-
-    fn handle_repl_loop(&mut self, config: L::Config) {
-        use linefeed::ReadResult::*;
-
-        'main: loop {
-            macro_rules! match_or_break {
-                ($line:expr) => {
-                    match $line {
-                        Err(e) => {
-                            println!("readline IO Error: {}", e);
-                            break 'main;
-                        }
-                        Ok(Eof) | Ok(Signal(_)) => break 'main,
-                        Ok(Input(ref input)) => input,
-                    }
-                };
-            }
-            self.update_line_reader();
-            let line = self.line_reader.read_line();
-            let input: &str = match_or_break!(line);
-
-            self.line_reader.add_history_unique(input.to_string());
-            let mut chars = input.chars().peekable();
-            let repl_responses = match chars.next() {
-                Some(ch) if ch == self.sigil =>
-                    if chars.peek() == Some(&'{') {
-                        let mut buf = String::new();
-                        buf.push_str(input.get(2..).unwrap());
-                        'multiline: loop {
-                            self.set_prompt(PromptStyle::Multiline);
-                            let new_line = self.line_reader.read_line();
-                            let new_input = match_or_break!(new_line);
-                            if new_input.starts_with(":}") {
-                                break 'multiline;
-                            } else {
-                                buf.push_str(new_input);
-                                buf.push('\n');
-                            }
-                        }
-                        self.handle_input(&buf, &config)
-                    } else {
-                        if let Some(output) = self.handle_interpreter_directive(input.get(1..).unwrap()) {
-                            println!("{}", output);
-                        }
-                        continue;
-                    },
-                _ => self.handle_input(input, &config),
-            };
-
-            for repl_response in repl_responses.iter() {
-                println!("{}", repl_response);
-            }
-        }
-    }
-
-    fn update_line_reader(&mut self) {
-        let tab_complete_handler = TabCompleteHandler::new(self.sigil, self.get_directives());
-        self.line_reader.set_completer(Arc::new(tab_complete_handler)); //TODO fix this here
-        self.set_prompt(PromptStyle::Normal);
-    }
-
-    fn set_prompt(&mut self, prompt_style: PromptStyle) {
-        let prompt_str = match prompt_style {
-            PromptStyle::Normal => ">> ",
-            PromptStyle::Multiline => ">| ",
-        };
-
-        self.line_reader.set_prompt(prompt_str).unwrap();
-    }
-
-    fn save_before_exit(&self) {
-        self.line_reader.save_history(HISTORY_SAVE_FILE).unwrap_or(());
-        self.options.save_to_file(OPTIONS_SAVE_FILE);
-    }
-
-    fn handle_interpreter_directive(&mut self, input: &str) -> InterpreterDirectiveOutput {
-        let arguments: Vec<&str> = input.split_whitespace().collect();
-
-        if arguments.is_empty() {
-            return None;
-        }
-
-        let directives = self.get_directives();
-        directives.perform(self, &arguments)
-    }
-
-    fn handle_input(&mut self, input: &str, config: &L::Config) -> Vec<ReplResponse> {
-        let mut debug_requests = HashSet::new();
-        for ask in self.options.debug_asks.iter() {
-            debug_requests.insert(ask.clone());
-        }
-
-        let request = ComputationRequest { source: input, config: config.clone(), debug_requests };
-        let response = self.language_state.run_computation(request);
-        response::handle_computation_response(response, &self.options)
-    }
-
-    fn get_directives(&mut self) -> CommandTree {
-        let pass_names = match self.language_state.request_meta(LangMetaRequest::StageNames) {
-            LangMetaResponse::StageNames(names) => names,
-            _ => vec![],
-        };
-
-        directives_from_pass_names(&pass_names)
-    }
-}
-
-struct TabCompleteHandler {
-    sigil: char,
-    top_level_commands: CommandTree,
-}
-
-use linefeed::{
-    complete::{Completer, Completion},
-    terminal::Terminal,
-};
-
-impl TabCompleteHandler {
-    fn new(sigil: char, top_level_commands: CommandTree) -> TabCompleteHandler {
-        TabCompleteHandler { top_level_commands, sigil }
-    }
-}
-
-impl<T: Terminal> Completer<T> for TabCompleteHandler {
-    fn complete(
-        &self,
-        word: &str,
-        prompter: &::linefeed::prompter::Prompter<T>,
-        start: usize,
-        _end: usize,
-    ) -> Option<Vec<Completion>> {
-        let line = prompter.buffer();
-
-        if !line.starts_with(self.sigil) {
-            return None;
-        }
-
-        let mut words = line[1..(if start == 0 { 1 } else { start })].split_whitespace();
-        let mut completions = Vec::new();
-        let mut command_tree: Option<&CommandTree> = Some(&self.top_level_commands);
-
-        loop {
-            match words.next() {
-                None => {
-                    let top = matches!(command_tree, Some(CommandTree::Top(_)));
-                    let word = if top { word.get(1..).unwrap() } else { word };
-                    for cmd in command_tree.map(|x| x.get_subcommands()).unwrap_or_default().into_iter() {
-                        if cmd.starts_with(word) {
-                            completions.push(Completion {
-                                completion: format!("{}{}", if top { ":" } else { "" }, cmd),
-                                display: Some(cmd.to_string()),
-                                suffix: ::linefeed::complete::Suffix::Some(' '),
-                            })
-                        }
-                    }
-                    break;
-                }
-                Some(s) => {
-                    let new_ptr: Option<&CommandTree> = command_tree.and_then(|cm| match cm {
-                        CommandTree::Top(children) => children.iter().find(|c| c.get_cmd() == s),
-                        CommandTree::NonTerminal { children, .. } =>
-                            children.iter().find(|c| c.get_cmd() == s),
-                        CommandTree::Terminal { children, .. } => children.iter().find(|c| c.get_cmd() == s),
-                    });
-                    command_tree = new_ptr;
-                }
-            }
-        }
-        Some(completions)
-    }
+fn command_line_options() -> getopts::Options {
+  let mut options = getopts::Options::new();
+  options.optflag("h",
+                  "help",
+                  "Show help text");
+  options.optflag("w",
+                  "webapp",
+                  "Start up web interpreter");
+  options
 }

schala-repl/src/repl/directives.rs

@@ -0,0 +1,126 @@
+use std::fmt::Write as FmtWrite;
+use itertools::Itertools;
+
+use crate::repl::Repl;
+use crate::repl::old_command_tree::OldCommandTree;
+use crate::language::{LangMetaRequest, LangMetaResponse, DebugAsk, DebugResponse}; 
+
+pub fn directives_from_pass_names(pass_names: &Vec<String>) -> OldCommandTree {
+  let passes_directives: Vec<OldCommandTree> = pass_names.iter()
+    .map(|pass_name| { OldCommandTree::nonterm_no_further_tab_completions(pass_name, None) })
+    .collect();
+
+  OldCommandTree::Top(vec![
+    OldCommandTree::terminal("exit", Some("exit the REPL"), vec![], Box::new(|repl: &mut Repl, _cmds: &[&str]| {
+      repl.save_before_exit();
+      ::std::process::exit(0)
+    })),
+    OldCommandTree::terminal("quit", Some("exit the REPL"), vec![], Box::new(|repl: &mut Repl, _cmds: &[&str]| {
+      repl.save_before_exit();
+      ::std::process::exit(0)
+    })),
+    OldCommandTree::terminal("help", Some("Print this help message"), vec![], Box::new(|repl: &mut Repl, cmds: &[&str]| {
+      Some(repl.print_help_message(cmds))
+    })),
+    OldCommandTree::nonterm("debug",
+      Some("Configure debug information"),
+      vec![
+        OldCommandTree::terminal("list-passes", Some("List all registered compiler passes"), vec![], Box::new(|repl: &mut Repl, _cmds: &[&str]| {
+          let language_state = repl.get_cur_language_state();
+          let pass_names = match language_state.request_meta(LangMetaRequest::StageNames) {
+            LangMetaResponse::StageNames(names) => names,
+            _ => vec![],
+          };
+
+          let mut buf = String::new();
+          for pass in pass_names.iter().map(|name| Some(name)).intersperse(None) {
+            match pass {
+              Some(pass) => write!(buf, "{}", pass).unwrap(),
+              None => write!(buf, " -> ").unwrap(),
+            }
+          }
+          Some(buf)
+        })),
+        OldCommandTree::terminal("show-immediate", None, passes_directives.clone(),
+        Box::new(|repl: &mut Repl, cmds: &[&str]| {
+          let cur_state = repl.get_cur_language_state();
+          let stage_name = match cmds.get(1) {
+            Some(s) => s.to_string(),
+            None => return Some(format!("Must specify a thing to debug")),
+          };
+          let meta = LangMetaRequest::ImmediateDebug(DebugAsk::ByStage { stage_name: stage_name.clone() });
+
+          let response = match cur_state.request_meta(meta) {
+            LangMetaResponse::ImmediateDebug(DebugResponse { ask, value }) => {
+              if (ask != DebugAsk::ByStage { stage_name: stage_name }) {
+                return Some(format!("Didn't get debug stage requested"));
+              }
+              value
+            },
+            _ => return Some(format!("Invalid language meta response")),
+          };
+          Some(response)
+        })),
+        OldCommandTree::terminal("show", None, passes_directives.clone(), Box::new(|repl: &mut Repl, cmds: &[&str]| {
+          let stage_name = match cmds.get(0) {
+            Some(s) => s.to_string(),
+            None => return Some(format!("Must specify a stage to show")),
+          };
+          let ask = DebugAsk::ByStage { stage_name };
+          repl.options.debug_asks.insert(ask);
+          None
+        })),
+        OldCommandTree::terminal("hide", None, passes_directives.clone(), Box::new(|repl: &mut Repl, cmds: &[&str]| {
+          let stage_name = match cmds.get(0) {
+            Some(s) => s.to_string(),
+            None => return Some(format!("Must specify a stage to hide")),
+          };
+          let ask = DebugAsk::ByStage { stage_name };
+          repl.options.debug_asks.remove(&ask);
+          None
+        })),
+        OldCommandTree::nonterm("total-time", None, vec![
+          OldCommandTree::terminal("on", None, vec![], Box::new(|repl: &mut Repl, _: &[&str]| {
+            repl.options.show_total_time = true;
+            None
+          })),
+          OldCommandTree::terminal("off", None, vec![], Box::new(turn_off)),
+        ]),
+        OldCommandTree::nonterm("stage-times", Some("Computation time per-stage"), vec![
+          OldCommandTree::terminal("on", None, vec![], Box::new(|repl: &mut Repl, _: &[&str]| {
+            repl.options.show_stage_times = true;
+            None
+          })),
+          OldCommandTree::terminal("off", None, vec![], Box::new(|repl: &mut Repl, _: &[&str]|  {
+            repl.options.show_stage_times = false;
+            None
+          })),
+        ])
+      ]
+    ),
+    OldCommandTree::nonterm("lang",
+      Some("switch between languages, or go directly to a langauge by name"),
+      vec![
+        OldCommandTree::nonterm_no_further_tab_completions("next", None),
+        OldCommandTree::nonterm_no_further_tab_completions("prev", None),
+        OldCommandTree::nonterm("go", None, vec![]),
+      ]
+    ),
+    OldCommandTree::terminal("doc", Some("Get language-specific help for an item"), vec![], Box::new(|repl: &mut Repl, cmds: &[&str]| {
+      cmds.get(0).map(|cmd| {
+        let source = cmd.to_string();
+        let meta = LangMetaRequest::Docs { source };
+        let cur_state = repl.get_cur_language_state();
+        match cur_state.request_meta(meta) {
+          LangMetaResponse::Docs { doc_string } => Some(doc_string),
+          _ => Some(format!("Invalid doc response"))
+        }
+      }).unwrap_or(Some(format!(":docs needs an argument")))
+    }))
+  ])
+}
+
+fn turn_off(repl: &mut Repl, _cmds: &[&str]) -> Option<String> {
+  repl.options.show_total_time = false;
+  None
+}

schala-repl/src/repl/mod.rs

@@ -0,0 +1,302 @@
+use std::fmt::Write as FmtWrite;
+use std::sync::Arc;
+use std::collections::HashSet;
+
+use colored::*;
+use crate::language::{ProgrammingLanguageInterface,
+ComputationRequest, ComputationResponse,
+DebugAsk, LangMetaResponse, LangMetaRequest};
+
+mod old_command_tree;
+use self::old_command_tree::{OldCommandTree, BoxedCommandFunction};
+mod repl_options;
+use repl_options::ReplOptions;
+mod directives;
+use directives::directives_from_pass_names;
+
+const HISTORY_SAVE_FILE: &'static str = ".schala_history";
+const OPTIONS_SAVE_FILE: &'static str = ".schala_repl";
+
+pub struct Repl {
+  interpreter_directive_sigil: char,
+  line_reader: ::linefeed::interface::Interface<::linefeed::terminal::DefaultTerminal>,
+  language_states: Vec<Box<ProgrammingLanguageInterface>>,
+  options: ReplOptions,
+  directives: OldCommandTree,
+}
+
+impl Repl {
+  pub fn new(mut initial_states: Vec<Box<ProgrammingLanguageInterface>>) -> Repl {
+    use linefeed::Interface;
+    let line_reader = Interface::new("schala-repl").unwrap();
+    let interpreter_directive_sigil = ':';
+
+    let pass_names = match initial_states[0].request_meta(LangMetaRequest::StageNames) {
+      LangMetaResponse::StageNames(names) => names,
+      _ => vec![],
+    };
+
+    Repl {
+      interpreter_directive_sigil,
+      line_reader,
+      language_states: initial_states,
+      options: ReplOptions::new(),
+      directives: directives_from_pass_names(&pass_names)
+    }
+  }
+
+  pub fn run_repl(&mut self) {
+    println!("Schala MetaInterpreter version {}", crate::VERSION_STRING);
+    println!("Type {}help for help with the REPL", self.interpreter_directive_sigil);
+    self.load_options();
+    self.handle_repl_loop();
+    self.save_before_exit();
+    println!("Exiting...");
+  }
+
+  fn load_options(&mut self) {
+    self.line_reader.load_history(HISTORY_SAVE_FILE).unwrap_or(());
+    match ReplOptions::load_from_file(OPTIONS_SAVE_FILE) {
+      Ok(options) => {
+        self.options = options;
+      },
+      Err(()) => ()
+    };
+  }
+
+  fn handle_repl_loop(&mut self) {
+    use linefeed::ReadResult::*;
+
+    loop {
+      self.update_line_reader();
+      match self.line_reader.read_line() {
+        Err(e) => {
+          println!("readline IO Error: {}", e);
+          break;
+        },
+        Ok(Eof) | Ok(Signal(_)) => break,
+        Ok(Input(ref input)) => {
+          self.line_reader.add_history_unique(input.to_string());
+          let output = match input.chars().nth(0) {
+            Some(ch) if ch == self.interpreter_directive_sigil => self.handle_interpreter_directive(input),
+            _ => Some(self.handle_input(input)),
+          };
+          if let Some(o) = output {
+            println!("=> {}", o);
+          }
+        }
+      }
+    }
+  }
+
+  fn update_line_reader(&mut self) {
+    let tab_complete_handler = TabCompleteHandler::new(self.interpreter_directive_sigil, self.get_directives());
+    self.line_reader.set_completer(Arc::new(tab_complete_handler)); //TODO fix this here
+    let prompt_str = format!(">> ");
+    self.line_reader.set_prompt(&prompt_str).unwrap();
+  }
+
+  fn save_before_exit(&self) {
+    self.line_reader.save_history(HISTORY_SAVE_FILE).unwrap_or(());
+    self.options.save_to_file(OPTIONS_SAVE_FILE);
+  }
+
+  fn get_function_from_directives<'a>(directives: &'a OldCommandTree, commands: &Vec<&str>) -> Result<(&'a BoxedCommandFunction, usize), String> {
+    let mut dir_pointer: &OldCommandTree = &directives;
+    let mut idx = 0;
+
+    loop {
+      match dir_pointer {
+        OldCommandTree::Top(subcommands) | OldCommandTree::NonTerminal { children: subcommands, .. } => {
+          let next_command = match commands.get(idx) {
+            Some(cmd) => cmd,
+            None => break Err(format!("Command requires arguments"))
+          };
+          idx += 1;
+          match subcommands.iter().find(|sc| sc.get_cmd() == *next_command) {
+            Some(command_tree) => {
+              dir_pointer = command_tree;
+            },
+            None => break Err(format!("Command {} not found", next_command))
+          };
+        },
+        OldCommandTree::Terminal { function, .. } => {
+          break Ok((function, idx));
+        },
+      }
+    }
+  }
+
+  fn handle_interpreter_directive(&mut self, input: &str) -> Option<String> {
+    let mut iter = input.chars();
+    iter.next();
+    let commands: Vec<&str> = iter
+      .as_str()
+      .split_whitespace()
+      .collect();
+
+    if commands.len() < 1 {
+      return None;
+    }
+
+    let directives = self.get_directives();
+    let result: Result<(&BoxedCommandFunction, _), String> = Repl::get_function_from_directives(&directives, &commands);
+    match result {
+      Ok((f, idx)) => f(self, &commands[idx..]),
+      Err(err) => Some(err.red().to_string())
+    }
+  }
+
+  fn print_help_message(&mut self, commands_passed_to_help: &[&str] ) -> String {
+    let mut buf = String::new();
+    let directives = match self.get_directives() {
+      OldCommandTree::Top(children) => children,
+      _ => panic!("Top-level OldCommandTree not Top")
+    };
+
+    match commands_passed_to_help {
+      [] => {
+        writeln!(buf, "MetaInterpreter options").unwrap();
+        writeln!(buf, "-----------------------").unwrap();
+
+        for directive in directives {
+          let trailer = " ";
+          writeln!(buf, "{}{}- {}", directive.get_cmd(), trailer, directive.get_help()).unwrap();
+        }
+
+        let ref lang = self.get_cur_language_state();
+        writeln!(buf, "").unwrap();
+        writeln!(buf, "Language-specific help for {}", lang.get_language_name()).unwrap();
+        writeln!(buf, "-----------------------").unwrap();
+      },
+      _ => {
+        writeln!(buf, "Command-specific help not available yet").unwrap();
+      }
+    };
+    buf
+  }
+
+  fn get_cur_language_state(&mut self) -> &mut Box<ProgrammingLanguageInterface> {
+    //TODO this is obviously not complete
+    &mut self.language_states[0]
+  }
+
+  fn handle_input(&mut self, input: &str) -> String {
+    let mut debug_requests = HashSet::new();
+    for ask in self.options.debug_asks.iter() {
+      debug_requests.insert(ask.clone());
+    }
+
+    let request = ComputationRequest {
+      source: input,
+      debug_requests,
+    };
+
+    let ref mut language_state = self.get_cur_language_state();
+    let response = language_state.run_computation(request);
+
+    self.handle_computation_response(response)
+  }
+
+  fn handle_computation_response(&mut self, response: ComputationResponse) -> String {
+    let mut buf = String::new();
+
+    if self.options.show_total_time {
+      buf.push_str(&format!("Total duration: {:?}\n", response.global_output_stats.total_duration));
+    }
+
+    if self.options.show_stage_times {
+      buf.push_str(&format!("{:?}\n", response.global_output_stats.stage_durations));
+    }
+
+
+    for debug_resp in response.debug_responses {
+      let stage_name = match debug_resp.ask {
+        DebugAsk::ByStage { stage_name } => stage_name,
+        _ => continue,
+      };
+      let s = format!("{} - {}\n", stage_name, debug_resp.value);
+      buf.push_str(&s);
+    }
+
+    buf.push_str(&match response.main_output {
+      Ok(s) => s,
+      Err(e) => format!("{} {}", "Error".red(), e)
+    });
+
+    buf
+  }
+
+  fn get_directives(&mut self) -> OldCommandTree {
+    let language_state = self.get_cur_language_state();
+    let pass_names = match language_state.request_meta(LangMetaRequest::StageNames) {
+      LangMetaResponse::StageNames(names) => names,
+      _ => vec![],
+    };
+
+    directives_from_pass_names(&pass_names)
+  }
+}
+
+
+struct TabCompleteHandler {
+  sigil: char,
+  top_level_commands: OldCommandTree,
+}
+
+use linefeed::complete::{Completion, Completer};
+use linefeed::terminal::Terminal;
+
+impl TabCompleteHandler {
+  fn new(sigil: char, top_level_commands: OldCommandTree) -> TabCompleteHandler {
+    TabCompleteHandler {
+      top_level_commands,
+      sigil,
+    }
+  }
+}
+
+impl<T: Terminal> Completer<T> for TabCompleteHandler {
+  fn complete(&self, word: &str, prompter: &::linefeed::prompter::Prompter<T>, start: usize, _end: usize) -> Option<Vec<Completion>> {
+    let line = prompter.buffer();
+
+    if !line.starts_with(self.sigil) {
+      return None;
+    }
+
+    let mut words = line[1..(if start == 0 { 1 } else { start })].split_whitespace();
+    let mut completions = Vec::new();
+    let mut command_tree: Option<&OldCommandTree> = Some(&self.top_level_commands);
+
+    loop {
+      match words.next() {
+        None => {
+          let top = match command_tree {
+            Some(OldCommandTree::Top(_)) => true,
+            _ => false
+          };
+          let word = if top { word.get(1..).unwrap() } else { word };
+          for cmd in command_tree.map(|x| x.get_children()).unwrap_or(vec![]).into_iter() {
+            if cmd.starts_with(word) {
+              completions.push(Completion {
+                completion: format!("{}{}", if top { ":" } else { "" }, cmd),
+                display: Some(cmd.to_string()),
+                suffix: ::linefeed::complete::Suffix::Some(' ')
+              })
+            }
+          }
+          break;
+        },
+        Some(s) => {
+          let new_ptr: Option<&OldCommandTree> = command_tree.and_then(|cm| match cm {
+            OldCommandTree::Top(children) => children.iter().find(|c| c.get_cmd() == s),
+            OldCommandTree::NonTerminal { children, .. } => children.iter().find(|c| c.get_cmd() == s),
+            OldCommandTree::Terminal { children, .. } => children.iter().find(|c| c.get_cmd() == s),
+          });
+          command_tree = new_ptr;
+        }
+      }
+    }
+    Some(completions)
+  }
+}

schala-repl/src/repl/old_command_tree.rs

@@ -0,0 +1,73 @@
+use super::Repl;
+
+pub type BoxedCommandFunction = Box<(fn(&mut Repl, &[&str]) -> Option<String>)>;
+
+/// A OldCommandTree is either a `Terminal` or a `NonTerminal`. When command parsing reaches the first
+/// Terminal, it will execute the `BoxedCommandFunction` found there with any remaining arguments
+#[derive(Clone)]
+pub enum OldCommandTree {
+  Terminal {
+    name: String,
+    children: Vec<OldCommandTree>,
+    help_msg: Option<String>,
+    function: BoxedCommandFunction,
+  },
+  NonTerminal {
+    name: String,
+    children: Vec<OldCommandTree>,
+    help_msg: Option<String>,
+  },
+  Top(Vec<OldCommandTree>),
+}
+
+impl OldCommandTree {
+  pub fn nonterm_no_further_tab_completions(s: &str, help: Option<&str>) -> OldCommandTree {
+    OldCommandTree::NonTerminal {name: s.to_string(), help_msg: help.map(|x| x.to_string()), children: vec![] }
+  }
+
+  pub fn terminal(s: &str, help: Option<&str>, children: Vec<OldCommandTree>, function: BoxedCommandFunction) -> OldCommandTree {
+    OldCommandTree::Terminal {name: s.to_string(), help_msg: help.map(|x| x.to_string()), function, children }
+  }
+
+  pub fn nonterm(s: &str, help: Option<&str>, children: Vec<OldCommandTree>) -> OldCommandTree {
+    OldCommandTree::NonTerminal {
+      name: s.to_string(),
+      help_msg: help.map(|x| x.to_string()),
+      children,
+    }
+  }
+
+  /*
+  pub fn nonterm_with_function(s: &str, help: Option<&str>, children: Vec<OldCommandTree>, func: BoxedCommandFunction) -> OldCommandTree {
+    OldCommandTree::NonTerminal {
+      name: s.to_string(),
+      help_msg: help.map(|x| x.to_string()),
+      children,
+      function: Some(func),
+    }
+  }
+  */
+
+  pub fn get_cmd(&self) -> &str {
+    match self {
+      OldCommandTree::Terminal { name, .. } => name.as_str(),
+      OldCommandTree::NonTerminal {name, ..} => name.as_str(),
+      OldCommandTree::Top(_) => "",
+    }
+  }
+  pub fn get_help(&self) -> &str {
+    match self {
+      OldCommandTree::Terminal { help_msg, ..} => help_msg.as_ref().map(|s| s.as_str()).unwrap_or(""),
+      OldCommandTree::NonTerminal { help_msg, .. } => help_msg.as_ref().map(|s| s.as_str()).unwrap_or(""),
+      OldCommandTree::Top(_) => ""
+    }
+  }
+  pub fn get_children(&self) -> Vec<&str> {
+    use OldCommandTree::*;
+    match self {
+      Terminal { children, .. } |
+      NonTerminal { children, .. } |
+      Top(children) => children.iter().map(|x| x.get_cmd()).collect()
+    }
+  }
+}

schala-repl/src/repl/repl_options.rs

@@ -0,0 +1,47 @@
+use crate::language::DebugAsk;
+
+use std::io::{Read, Write};
+use std::collections::HashSet;
+use std::fs::File;
+
+#[derive(Serialize, Deserialize)]
+pub struct ReplOptions {
+  pub debug_asks: HashSet<DebugAsk>,
+  pub show_total_time: bool,
+  pub show_stage_times: bool,
+}
+
+impl ReplOptions {
+  pub fn new() -> ReplOptions {
+    ReplOptions {
+      debug_asks: HashSet::new(),
+      show_total_time: true,
+      show_stage_times: false,
+    }
+  }
+
+  pub fn save_to_file(&self, filename: &str) {
+    let res = File::create(filename)
+      .and_then(|mut file| {
+        let buf = crate::serde_json::to_string(self).unwrap();
+        file.write_all(buf.as_bytes())
+      });
+    if let Err(err) = res {
+      println!("Error saving {} file {}", filename, err);
+    }
+  }
+
+  pub fn load_from_file(filename: &str) -> Result<ReplOptions, ()> {
+    File::open(filename)
+      .and_then(|mut file| {
+        let mut contents = String::new();
+        file.read_to_string(&mut contents)?;
+        Ok(contents)
+      })
+    .and_then(|contents| {
+      let output: ReplOptions = crate::serde_json::from_str(&contents)?;
+      Ok(output)
+    })
+    .map_err(|_| ())
+  }
+}

schala-repl/src/repl_options.rs

@@ -1,43 +0,0 @@
-use std::{
-    collections::HashSet,
-    fs::File,
-    io::{self, Read, Write},
-};
-
-use crate::language::DebugAsk;
-
-#[derive(Serialize, Deserialize)]
-pub struct ReplOptions {
-    pub debug_asks: HashSet<DebugAsk>,
-    pub show_total_time: bool,
-    pub show_stage_times: bool,
-}
-
-impl ReplOptions {
-    pub fn new() -> ReplOptions {
-        ReplOptions { debug_asks: HashSet::new(), show_total_time: true, show_stage_times: false }
-    }
-
-    pub fn save_to_file(&self, filename: &str) {
-        let res = File::create(filename).and_then(|mut file| {
-            let buf = crate::serde_json::to_string(self).unwrap();
-            file.write_all(buf.as_bytes())
-        });
-        if let Err(err) = res {
-            eprintln!("Error saving {} file {}", filename, err);
-        }
-    }
-
-    pub fn load_from_file(filename: &str) -> Result<ReplOptions, io::Error> {
-        File::open(filename)
-            .and_then(|mut file| {
-                let mut contents = String::new();
-                file.read_to_string(&mut contents)?;
-                Ok(contents)
-            })
-            .and_then(|contents| {
-                let output: ReplOptions = crate::serde_json::from_str(&contents)?;
-                Ok(output)
-            })
-    }
-}

schala-repl/src/response.rs

@@ -1,74 +0,0 @@
-use std::{fmt, fmt::Write};
-
-use colored::*;
-
-use crate::{
-    language::{ComputationResponse, DebugAsk},
-    ReplOptions,
-};
-
-pub struct ReplResponse {
-    label: Option<String>,
-    text: String,
-    color: Option<Color>,
-}
-
-impl fmt::Display for ReplResponse {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        let mut buf = String::new();
-        if let Some(ref label) = self.label {
-            write!(buf, "({})", label).unwrap();
-        }
-        write!(buf, "=> {}", self.text).unwrap();
-        write!(
-            f,
-            "{}",
-            match self.color {
-                Some(c) => buf.color(c),
-                None => buf.normal(),
-            }
-        )
-    }
-}
-
-pub fn handle_computation_response(
-    response: ComputationResponse,
-    options: &ReplOptions,
-) -> Vec<ReplResponse> {
-    let mut responses = vec![];
-
-    if options.show_total_time {
-        responses.push(ReplResponse {
-            label: Some("Total time".to_string()),
-            text: format!("{:?}", response.global_output_stats.total_duration),
-            color: None,
-        });
-    }
-
-    if options.show_stage_times {
-        responses.push(ReplResponse {
-            label: Some("Stage times".to_string()),
-            text: format!("{:?}", response.global_output_stats.stage_durations),
-            color: None,
-        });
-    }
-
-    for debug_resp in response.debug_responses {
-        let stage_name = match debug_resp.ask {
-            DebugAsk::ByStage { stage_name, .. } => stage_name,
-            _ => continue,
-        };
-        responses.push(ReplResponse {
-            label: Some(stage_name.to_string()),
-            text: debug_resp.value,
-            color: Some(Color::Red),
-        });
-    }
-
-    responses.push(match response.main_output {
-        Ok(s) => ReplResponse { label: None, text: s, color: None },
-        Err(e) => ReplResponse { label: Some("Error".to_string()), text: e, color: Some(Color::Red) },
-    });
-
-    responses
-}

source_files/schala/syntax_playground.schala

@@ -6,37 +6,36 @@ fn main() {
 
 }
 
-
-@annotations use the @ sigil
+@annotations are with @-
 
 // variable expressions
-  //variable declaration works like Rust
-  let a: I32 = 20
-  let mut b: String = 20
+  var a: I32 = 20
+  const b: String = 20
 
   there(); can(); be(); multiple(); statements(); per_line();
 
   //string interpolation
-  // maybe
-  let yolo = "I have ${a + b} people in my house"
+  const yolo = "I have ${a + b} people in my house"
 
-  // let expressions
+  // let expressions ??? not sure if I want this
   let a = 10, b = 20, c = 30 in a + b + c
 
   //list literal
-  let q = [1,2,3,4]
+  const q = [1,2,3,4]
 
-  //lambda literal - uses haskell-ish syntax
-  q.map(\(item) { item * 100 })
+  //lambda literal 
+  q.map({|item| item * 100 })
 
   fn yolo(a: MyType, b: YourType): ReturnType<Param1, Param2> {
     if a == 20 {
       return "early"
     }
+    var sex = 20
+    sex
   }
 
+
 /* for/while loop topics */
-//TODO I can probably get away with having one of `for`, `while`
 
    //infinite loop
    while {
@@ -60,7 +59,7 @@ fn main() {
   //monadic decomposition
   for {
     a <- maybeInt();
-    s <- foo()
+    s <- foo() 
   } return {
     a + s
   } //return type is Monad<return type of block>
@@ -71,13 +70,13 @@ fn main() {
 
 /* conditionals/pattern matching */
 
-// `is` functions as an operator asking "does this pattern match"
+// "is" operator for "does this pattern match"
 
 x is Some(t) // type bool
 
 if x {
   is Some(t) => {
-  }
+  },
   is None => {
 
   }
@@ -87,7 +86,7 @@ if x {
  //syntax is, I guess, for <expr> <brace-block>, where <expr> is a bool, or a <arrow-expr>
 
  // type level alises
- type alias <name> = <other type> #maybe thsi should be 'alias'?
+ typealias <name> = <other type> #maybe thsi should be 'alias'?
 
 /*
 what if type A = B meant that you could had to create A's with A(B), but when you used A's the interface was exactly like B's?
@@ -95,12 +94,12 @@ what if type A = B meant that you could had to create A's with A(B), but when yo
  */
 
  //declaring types of all stripes
- type MyData = { a: i32, b: String } // shorthand special-case for `type MyData = MyData { a: i32, b: String }`
+ type MyData = { a: i32, b: String }
  type MyType = MyType
  type Option<a> = None | Some(a)
  type Signal = Absence | SimplePresence(i32) | ComplexPresence {a: i32, b: MyCustomData}
 
- //traits TODO I probably want to rename this
+ //traits
  
  trait Bashable { }
  trait Luggable {
@@ -109,7 +108,7 @@ what if type A = B meant that you could had to create A's with A(B), but when yo
 
 }
 
-// lambdas - maybe I want to use ruby-style (not rust style) syntax
-// e.g.
-// Also TODO Nix uses `X: Y: Z` for in its value-level syntax, why can't I?
-let a: X -> Y -> Z = {|x,y|  }
+
+// lambdas
+// ruby-style not rust-style
+const a: X -> Y -> Z = {|x,y|  }

src/main.rs

@@ -1,71 +1,15 @@
-use std::{collections::HashSet, fs::File, io::Read, path::PathBuf, process::exit};
+extern crate schala_repl;
 
-use schala_lang::{Schala, SchalaConfig};
-use schala_repl::{ComputationRequest, ProgrammingLanguageInterface, Repl};
+//extern crate maaru_lang;
+//extern crate rukka_lang;
+//extern crate robo_lang;
+extern crate schala_lang;
+use schala_repl::{ProgrammingLanguageInterface, start_repl};
+
+extern { }
 
-//TODO specify multiple langs, and have a way to switch between them
 fn main() {
-    let args: Vec<String> = std::env::args().collect();
-    let matches = command_line_options().parse(&args[1..]).unwrap_or_else(|e| {
-        eprintln!("Error parsing options: {}", e);
-        exit(1);
-    });
-
-    if matches.opt_present("help") {
-        println!("{}", command_line_options().usage("Schala metainterpreter"));
-        exit(0);
-    }
-
-    if matches.free.is_empty() {
-        let state = Schala::new();
-        let mut repl = Repl::new(state);
-        let config = SchalaConfig { repl: true };
-        repl.run_repl(config);
-    } else {
-        let paths: Vec<PathBuf> = matches.free.iter().map(PathBuf::from).collect();
-        //TODO handle more than one file
-        let filename = &paths[0];
-        let extension = filename.extension().and_then(|e| e.to_str()).unwrap_or_else(|| {
-            eprintln!("Source file `{}` has no extension.", filename.display());
-            exit(1);
-        });
-
-        //TODO this proably should be a macro for every supported language
-        if extension == Schala::source_file_suffix() {
-            let config = SchalaConfig { repl: false };
-
-            run_noninteractive(paths, Schala::new(), config);
-        } else {
-            eprintln!("Extension .{} not recognized", extension);
-            exit(1);
-        }
-    }
+  let langs: Vec<Box<ProgrammingLanguageInterface>> = vec![Box::new(schala_lang::Schala::new())];
+  start_repl(langs);
 }
 
-pub fn run_noninteractive<L: ProgrammingLanguageInterface>(
-    filenames: Vec<PathBuf>,
-    mut language: L,
-    config: L::Config,
-) {
-    // for now, ony do something with the first filename
-
-    let filename = &filenames[0];
-    let mut source_file = File::open(filename).unwrap();
-    let mut buffer = String::new();
-    source_file.read_to_string(&mut buffer).unwrap();
-
-    let request = ComputationRequest { source: &buffer, config, debug_requests: HashSet::new() };
-
-    let response = language.run_computation(request);
-    match response.main_output {
-        Ok(s) => println!("{}", s),
-        Err(s) => eprintln!("{}", s),
-    };
-}
-
-fn command_line_options() -> getopts::Options {
-    let mut options = getopts::Options::new();
-    options.optflag("h", "help", "Show help text");
-    //options.optflag("w", "webapp", "Start up web interpreter");
-    options
-}