Move reduced_ast.rs into multiple files
This commit is contained in:
Greg Shuflin
parent
0d488b250d
commit
2f669b77fd
@ -1,535 +0,0 @@
|
||||
//! # Reduced AST
|
||||
//! The reduced AST is a minimal AST designed to be built from the full AST after all possible
|
||||
//! static checks have been done. Consequently, the AST reduction phase does very little error
|
||||
//! checking itself - any errors should ideally be caught either by an earlier phase, or are
|
||||
//! runtime errors that the evaluator should handle. That said, becuase it does do table lookups
|
||||
//! that can in principle fail [especially at the moment with most static analysis not yet complete],
|
||||
//! there is an Expr variant `ReductionError` to handle these cases.
|
||||
//!
|
||||
//! A design decision to make - should the ReducedAST types contain all information about
|
||||
//! type/layout necessary for the evaluator to work? If so, then the evaluator should not
|
||||
//! have access to the symbol table at all and ReducedAST should carry that information. If not,
|
||||
//! then ReducedAST shouldn't be duplicating information that can be queried at runtime from the
|
||||
//! symbol table. But I think the former might make sense since ultimately the bytecode will be
|
||||
//! built from the ReducedAST.
|
||||
|
||||
#![allow(clippy::enum_variant_names)]
|
||||
|
||||
use std::rc::Rc;
|
||||
use std::str::FromStr;
|
||||
use std::convert::TryFrom;
|
||||
|
||||
use crate::ast::*;
|
||||
use crate::symbol_table::{Symbol, SymbolSpec, SymbolTable};
|
||||
use crate::builtin::Builtin;
|
||||
use crate::util::deref_optional_box;
|
||||
|
||||
#[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),
|
||||
Sym(Rc<String>), //a Sym is anything that can be looked up by name at runtime - i.e. a function or variable address
|
||||
Tuple(Vec<Expr>),
|
||||
Func(Func),
|
||||
Constructor {
|
||||
type_name: Rc<String>,
|
||||
name: Rc<String>,
|
||||
tag: usize,
|
||||
arity: usize, // n.b. arity here is always the value from the symbol table - if it doesn't match what it's being called with, that's an eval error, eval will handle it
|
||||
},
|
||||
Call {
|
||||
f: Box<Expr>,
|
||||
args: Vec<Expr>,
|
||||
},
|
||||
Assign {
|
||||
val: Box<Expr>, //TODO this probably can't be a val
|
||||
expr: Box<Expr>,
|
||||
},
|
||||
Conditional {
|
||||
cond: Box<Expr>,
|
||||
then_clause: Vec<Stmt>,
|
||||
else_clause: Vec<Stmt>,
|
||||
},
|
||||
ConditionalTargetSigilValue,
|
||||
CaseMatch {
|
||||
cond: Box<Expr>,
|
||||
alternatives: Vec<Alternative>
|
||||
},
|
||||
UnimplementedSigilValue,
|
||||
ReductionError(String),
|
||||
}
|
||||
|
||||
pub type BoundVars = Vec<Option<Rc<String>>>; //remember that order matters here
|
||||
|
||||
#[derive(Debug, Clone)]
|
||||
pub struct Alternative {
|
||||
pub matchable: Subpattern,
|
||||
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(Builtin),
|
||||
UserDefined {
|
||||
name: Option<Rc<String>>,
|
||||
params: Vec<Rc<String>>,
|
||||
body: Vec<Stmt>,
|
||||
}
|
||||
}
|
||||
|
||||
pub fn reduce(ast: &AST, symbol_table: &SymbolTable) -> ReducedAST {
|
||||
let mut reducer = Reducer { symbol_table };
|
||||
reducer.ast(ast)
|
||||
}
|
||||
|
||||
struct Reducer<'a> {
|
||||
symbol_table: &'a SymbolTable
|
||||
}
|
||||
|
||||
impl<'a> Reducer<'a> {
|
||||
fn ast(&mut self, ast: &AST) -> ReducedAST {
|
||||
let mut output = vec![];
|
||||
for statement in ast.statements.iter() {
|
||||
output.push(self.statement(statement));
|
||||
}
|
||||
ReducedAST(output)
|
||||
}
|
||||
|
||||
fn statement(&mut self, stmt: &Statement) -> Stmt {
|
||||
match &stmt.kind {
|
||||
StatementKind::Expression(expr) => Stmt::Expr(self.expression(expr)),
|
||||
StatementKind::Declaration(decl) => self.declaration(decl),
|
||||
StatementKind::Import(_) => Stmt::Noop,
|
||||
StatementKind::Module(modspec) => {
|
||||
for statement in modspec.contents.iter() {
|
||||
self.statement(statement);
|
||||
}
|
||||
Stmt::Noop
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
#[allow(clippy::ptr_arg)]
|
||||
fn block(&mut self, block: &Block) -> Vec<Stmt> {
|
||||
block.iter().map(|stmt| self.statement(stmt)).collect()
|
||||
}
|
||||
|
||||
fn invocation_argument(&mut self, invoc: &InvocationArgument) -> Expr {
|
||||
use crate::ast::InvocationArgument::*;
|
||||
match invoc {
|
||||
Positional(ex) => self.expression(ex),
|
||||
Keyword { .. } => Expr::UnimplementedSigilValue,
|
||||
Ignored => Expr::UnimplementedSigilValue,
|
||||
}
|
||||
}
|
||||
|
||||
fn expression(&mut self, expr: &Expression) -> Expr {
|
||||
use crate::ast::ExpressionKind::*;
|
||||
let input = &expr.kind;
|
||||
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) => self.binop(binop, lhs, rhs),
|
||||
PrefixExp(op, arg) => self.prefix(op, arg),
|
||||
Value(qualified_name) => self.value(qualified_name),
|
||||
Call { f, arguments } => self.reduce_call_expression(f, arguments),
|
||||
TupleLiteral(exprs) => Expr::Tuple(exprs.iter().map(|e| self.expression(e)).collect()),
|
||||
IfExpression { discriminator, body } => self.reduce_if_expression(deref_optional_box(discriminator), body),
|
||||
Lambda { params, body, .. } => self.reduce_lambda(params, body),
|
||||
NamedStruct { name, fields } => self.reduce_named_struct(name, fields),
|
||||
Index { .. } => Expr::UnimplementedSigilValue,
|
||||
WhileExpression { .. } => Expr::UnimplementedSigilValue,
|
||||
ForExpression { .. } => Expr::UnimplementedSigilValue,
|
||||
ListLiteral { .. } => Expr::UnimplementedSigilValue,
|
||||
}
|
||||
}
|
||||
|
||||
fn value(&mut self, qualified_name: &QualifiedName) -> Expr {
|
||||
let Symbol { local_name, spec, .. } = match self.symbol_table.lookup_symbol(&qualified_name.id) {
|
||||
Some(s) => s,
|
||||
//TODO this causes several evaluation tests to fail, figure out what's going on here
|
||||
//None => return Expr::ReductionError(format!("Symbol {:?} not found", sym_name)),
|
||||
None => {
|
||||
let name = qualified_name.components.last().unwrap().clone();
|
||||
return Expr::Sym(name)
|
||||
}
|
||||
};
|
||||
|
||||
match spec {
|
||||
SymbolSpec::RecordConstructor { .. } => Expr::ReductionError("AST reducer doesn't expect a RecordConstructor here".to_string()),
|
||||
SymbolSpec::DataConstructor { index, arity, type_name } => Expr::Constructor {
|
||||
type_name: type_name.clone(),
|
||||
name: local_name.clone(),
|
||||
tag: *index,
|
||||
arity: *arity,
|
||||
},
|
||||
SymbolSpec::Func(_) => Expr::Sym(local_name.clone()),
|
||||
SymbolSpec::Binding => Expr::Sym(local_name.clone()), //TODO not sure if this is right, probably needs to eventually be fqsn
|
||||
}
|
||||
}
|
||||
|
||||
#[allow(clippy::ptr_arg)]
|
||||
fn reduce_lambda(&mut self, params: &[FormalParam], body: &Block) -> Expr {
|
||||
Expr::Func(Func::UserDefined {
|
||||
name: None,
|
||||
params: params.iter().map(|param| param.name.clone()).collect(),
|
||||
body: self.block(body),
|
||||
})
|
||||
}
|
||||
|
||||
fn reduce_named_struct(&mut self, name: &QualifiedName, fields: &[(Rc<String>, Expression)]) -> Expr {
|
||||
let symbol = match self.symbol_table.lookup_symbol(&name.id) {
|
||||
Some(fqsn) => fqsn,
|
||||
None => return Expr::ReductionError(format!("FQSN lookup for name {:?} failed", name)),
|
||||
};
|
||||
|
||||
let (type_name, index, members_from_table) = match &symbol.spec {
|
||||
SymbolSpec::RecordConstructor { members, type_name, index } => (type_name.clone(), index, members),
|
||||
_ => return Expr::ReductionError("Not a record constructor".to_string()),
|
||||
};
|
||||
|
||||
let arity = members_from_table.len();
|
||||
|
||||
let mut args: Vec<(Rc<String>, Expr)> = fields.iter()
|
||||
.map(|(name, expr)| (name.clone(), self.expression(expr)))
|
||||
.collect();
|
||||
|
||||
args.as_mut_slice()
|
||||
.sort_unstable_by(|(name1, _), (name2, _)| name1.cmp(name2)); //arbitrary - sorting by alphabetical order
|
||||
|
||||
let args = args.into_iter().map(|(_, expr)| expr).collect();
|
||||
|
||||
//TODO make sure this sorting actually works
|
||||
let f = box Expr::Constructor { type_name, name: symbol.local_name.clone(), tag: *index, arity, };
|
||||
Expr::Call { f, args }
|
||||
}
|
||||
|
||||
fn reduce_call_expression(&mut self, func: &Expression, arguments: &[ InvocationArgument ]) -> Expr {
|
||||
Expr::Call {
|
||||
f: Box::new(self.expression(func)),
|
||||
args: arguments.iter().map(|arg| self.invocation_argument(arg)).collect(),
|
||||
}
|
||||
}
|
||||
|
||||
fn reduce_if_expression(&mut self, discriminator: Option<&Expression>, body: &IfExpressionBody) -> Expr {
|
||||
let cond = Box::new(match discriminator {
|
||||
Some(expr) => self.expression(expr),
|
||||
None => return Expr::ReductionError("blank cond if-expr not supported".to_string()),
|
||||
});
|
||||
|
||||
match body {
|
||||
IfExpressionBody::SimpleConditional { then_case, else_case } => {
|
||||
let then_clause = self.block(then_case);
|
||||
let else_clause = match else_case.as_ref() {
|
||||
None => vec![],
|
||||
Some(stmts) => self.block(stmts),
|
||||
};
|
||||
Expr::Conditional { cond, then_clause, else_clause }
|
||||
},
|
||||
IfExpressionBody::SimplePatternMatch { pattern, then_case, else_case } => {
|
||||
let then_clause = self.block(then_case);
|
||||
let else_clause = match else_case.as_ref() {
|
||||
None => vec![],
|
||||
Some(stmts) => self.block(stmts),
|
||||
};
|
||||
|
||||
let alternatives = vec![
|
||||
pattern.to_alternative(then_clause, self.symbol_table),
|
||||
Alternative {
|
||||
matchable: Subpattern {
|
||||
tag: None,
|
||||
subpatterns: vec![],
|
||||
bound_vars: vec![],
|
||||
guard: None,
|
||||
},
|
||||
item: else_clause
|
||||
},
|
||||
];
|
||||
|
||||
Expr::CaseMatch {
|
||||
cond,
|
||||
alternatives,
|
||||
}
|
||||
},
|
||||
IfExpressionBody::CondList(ref condition_arms) => {
|
||||
let mut alternatives = vec![];
|
||||
for arm in condition_arms {
|
||||
match arm.condition {
|
||||
Condition::Expression(ref _expr) => {
|
||||
return Expr::UnimplementedSigilValue
|
||||
},
|
||||
Condition::Pattern(ref p) => {
|
||||
let item = self.block(&arm.body);
|
||||
let alt = p.to_alternative(item, self.symbol_table);
|
||||
alternatives.push(alt);
|
||||
},
|
||||
Condition::TruncatedOp(_, _) => {
|
||||
return Expr::UnimplementedSigilValue
|
||||
},
|
||||
Condition::Else => {
|
||||
return Expr::UnimplementedSigilValue
|
||||
}
|
||||
}
|
||||
}
|
||||
Expr::CaseMatch { cond, alternatives }
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
fn binop(&mut self, binop: &BinOp, lhs: &Expression, rhs: &Expression) -> Expr {
|
||||
let operation = Builtin::from_str(binop.sigil()).ok();
|
||||
match operation {
|
||||
Some(Builtin::Assignment) => Expr::Assign {
|
||||
val: Box::new(self.expression(&*lhs)),
|
||||
expr: Box::new(self.expression(&*rhs)),
|
||||
},
|
||||
Some(op) => {
|
||||
let f = Box::new(Expr::Func(Func::BuiltIn(op)));
|
||||
Expr::Call { f, args: vec![self.expression(&*lhs), self.expression(&*rhs)] }
|
||||
},
|
||||
None => {
|
||||
//TODO handle a user-defined operation
|
||||
Expr::UnimplementedSigilValue
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
fn prefix(&mut self, prefix: &PrefixOp, arg: &Expression) -> Expr {
|
||||
let builtin: Option<Builtin> = TryFrom::try_from(prefix).ok();
|
||||
match builtin {
|
||||
Some(op) => {
|
||||
let f = Box::new(Expr::Func(Func::BuiltIn(op)));
|
||||
Expr::Call { f, args: vec![self.expression(arg)] }
|
||||
},
|
||||
None => { //TODO need this for custom prefix ops
|
||||
Expr::UnimplementedSigilValue
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
fn declaration(&mut self, declaration: &Declaration) -> Stmt {
|
||||
use self::Declaration::*;
|
||||
match declaration {
|
||||
Binding {name, constant, expr, .. } => Stmt::Binding { name: name.clone(), constant: *constant, expr: self.expression(expr) },
|
||||
FuncDecl(Signature { name, params, .. }, statements) => Stmt::PreBinding {
|
||||
name: name.clone(),
|
||||
func: Func::UserDefined {
|
||||
name: Some(name.clone()),
|
||||
params: params.iter().map(|param| param.name.clone()).collect(),
|
||||
body: self.block(statements),
|
||||
}
|
||||
},
|
||||
TypeDecl { .. } => Stmt::Noop,
|
||||
TypeAlias{ .. } => Stmt::Noop,
|
||||
Interface { .. } => Stmt::Noop,
|
||||
Impl { .. } => Stmt::Expr(Expr::UnimplementedSigilValue),
|
||||
_ => Stmt::Expr(Expr::UnimplementedSigilValue)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
/* ig var pat
|
||||
* x is SomeBigOldEnum(_, x, Some(t))
|
||||
*/
|
||||
|
||||
fn handle_symbol(symbol: Option<&Symbol>, inner_patterns: &[Pattern], symbol_table: &SymbolTable) -> Subpattern {
|
||||
use self::Pattern::*;
|
||||
let tag = symbol.map(|symbol| match symbol.spec {
|
||||
SymbolSpec::DataConstructor { index, .. } => index,
|
||||
_ => 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 {
|
||||
VarOrName(qualified_name) => {
|
||||
let symbol_exists = symbol_table.lookup_symbol(&qualified_name.id).is_some();
|
||||
if symbol_exists {
|
||||
None
|
||||
} else {
|
||||
let QualifiedName { components, .. } = qualified_name;
|
||||
if components.len() == 1 {
|
||||
Some(components[0].clone())
|
||||
} else {
|
||||
panic!("Bad variable name in pattern");
|
||||
}
|
||||
}
|
||||
},
|
||||
_ => None,
|
||||
}).collect();
|
||||
|
||||
let subpatterns = inner_patterns.iter().map(|p| match p {
|
||||
Ignored => None,
|
||||
VarOrName(_) => 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 {
|
||||
matchable: Subpattern {
|
||||
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(QualifiedName{ components, id }, inner_patterns) => {
|
||||
match symbol_table.lookup_symbol(id) {
|
||||
Some(symbol) => handle_symbol(Some(symbol), inner_patterns, symbol_table),
|
||||
None => panic!("Symbol {:?} not found", components)
|
||||
}
|
||||
},
|
||||
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),
|
||||
VarOrName(QualifiedName { components, id }) => {
|
||||
// if symbol is Some, treat this as a symbol pattern. If it's None, treat it
|
||||
// as a variable.
|
||||
match symbol_table.lookup_symbol(id) {
|
||||
Some(symbol) => handle_symbol(Some(symbol), &[], symbol_table),
|
||||
None => {
|
||||
println!("Components: {:?}", components);
|
||||
let name = if components.len() == 1 {
|
||||
components[0].clone()
|
||||
} else {
|
||||
panic!("check this line of code yo");
|
||||
};
|
||||
Subpattern {
|
||||
tag: None,
|
||||
subpatterns: vec![],
|
||||
guard: None,
|
||||
bound_vars: vec![Some(name)],
|
||||
}
|
||||
}
|
||||
}
|
||||
},
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
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(-(*n as i64)),
|
||||
(true, ExpressionKind::FloatLiteral(f)) => Lit::Float(-f),
|
||||
_ => panic!("This should never happen")
|
||||
});
|
||||
let guard = Some(Expr::Call {
|
||||
f: Box::new(Expr::Func(Func::BuiltIn(Builtin::Equality))),
|
||||
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(Builtin::Equality))),
|
||||
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(Builtin::BooleanNot))),
|
||||
args: vec![Expr::ConditionalTargetSigilValue]
|
||||
}
|
||||
});
|
||||
Subpattern {
|
||||
tag: None,
|
||||
subpatterns: vec![],
|
||||
guard,
|
||||
bound_vars: vec![],
|
||||
}
|
||||
},
|
||||
}
|
||||
}
|
||||
|
||||
}
|
||||
513
schala-lang/language/src/reduced_ast/mod.rs
Normal file
513
schala-lang/language/src/reduced_ast/mod.rs
Normal file
@ -0,0 +1,513 @@
|
||||
//! # Reduced AST
|
||||
//! The reduced AST is a minimal AST designed to be built from the full AST after all possible
|
||||
//! static checks have been done. Consequently, the AST reduction phase does very little error
|
||||
//! checking itself - any errors should ideally be caught either by an earlier phase, or are
|
||||
//! runtime errors that the evaluator should handle. That said, becuase it does do table lookups
|
||||
//! that can in principle fail [especially at the moment with most static analysis not yet complete],
|
||||
//! there is an Expr variant `ReductionError` to handle these cases.
|
||||
//!
|
||||
//! A design decision to make - should the ReducedAST types contain all information about
|
||||
//! type/layout necessary for the evaluator to work? If so, then the evaluator should not
|
||||
//! have access to the symbol table at all and ReducedAST should carry that information. If not,
|
||||
//! then ReducedAST shouldn't be duplicating information that can be queried at runtime from the
|
||||
//! symbol table. But I think the former might make sense since ultimately the bytecode will be
|
||||
//! built from the ReducedAST.
|
||||
|
||||
use std::convert::TryFrom;
|
||||
use std::rc::Rc;
|
||||
use std::str::FromStr;
|
||||
|
||||
use crate::ast::*;
|
||||
use crate::builtin::Builtin;
|
||||
use crate::symbol_table::{Symbol, SymbolSpec, SymbolTable};
|
||||
use crate::util::deref_optional_box;
|
||||
|
||||
mod types;
|
||||
pub use types::*;
|
||||
|
||||
pub fn reduce(ast: &AST, symbol_table: &SymbolTable) -> ReducedAST {
|
||||
let mut reducer = Reducer { symbol_table };
|
||||
reducer.ast(ast)
|
||||
}
|
||||
|
||||
struct Reducer<'a> {
|
||||
symbol_table: &'a SymbolTable,
|
||||
}
|
||||
|
||||
impl<'a> Reducer<'a> {
|
||||
fn ast(&mut self, ast: &AST) -> ReducedAST {
|
||||
let mut output = vec![];
|
||||
for statement in ast.statements.iter() {
|
||||
output.push(self.statement(statement));
|
||||
}
|
||||
ReducedAST(output)
|
||||
}
|
||||
|
||||
fn statement(&mut self, stmt: &Statement) -> Stmt {
|
||||
match &stmt.kind {
|
||||
StatementKind::Expression(expr) => Stmt::Expr(self.expression(expr)),
|
||||
StatementKind::Declaration(decl) => self.declaration(decl),
|
||||
StatementKind::Import(_) => Stmt::Noop,
|
||||
StatementKind::Module(modspec) => {
|
||||
for statement in modspec.contents.iter() {
|
||||
self.statement(statement);
|
||||
}
|
||||
Stmt::Noop
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
#[allow(clippy::ptr_arg)]
|
||||
fn block(&mut self, block: &Block) -> Vec<Stmt> {
|
||||
block.iter().map(|stmt| self.statement(stmt)).collect()
|
||||
}
|
||||
|
||||
fn invocation_argument(&mut self, invoc: &InvocationArgument) -> Expr {
|
||||
use crate::ast::InvocationArgument::*;
|
||||
match invoc {
|
||||
Positional(ex) => self.expression(ex),
|
||||
Keyword { .. } => Expr::UnimplementedSigilValue,
|
||||
Ignored => Expr::UnimplementedSigilValue,
|
||||
}
|
||||
}
|
||||
|
||||
fn expression(&mut self, expr: &Expression) -> Expr {
|
||||
use crate::ast::ExpressionKind::*;
|
||||
let input = &expr.kind;
|
||||
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) => self.binop(binop, lhs, rhs),
|
||||
PrefixExp(op, arg) => self.prefix(op, arg),
|
||||
Value(qualified_name) => self.value(qualified_name),
|
||||
Call { f, arguments } => self.reduce_call_expression(f, arguments),
|
||||
TupleLiteral(exprs) => Expr::Tuple(exprs.iter().map(|e| self.expression(e)).collect()),
|
||||
IfExpression {
|
||||
discriminator,
|
||||
body,
|
||||
} => self.reduce_if_expression(deref_optional_box(discriminator), body),
|
||||
Lambda { params, body, .. } => self.reduce_lambda(params, body),
|
||||
NamedStruct { name, fields } => self.reduce_named_struct(name, fields),
|
||||
Index { .. } => Expr::UnimplementedSigilValue,
|
||||
WhileExpression { .. } => Expr::UnimplementedSigilValue,
|
||||
ForExpression { .. } => Expr::UnimplementedSigilValue,
|
||||
ListLiteral { .. } => Expr::UnimplementedSigilValue,
|
||||
}
|
||||
}
|
||||
|
||||
fn value(&mut self, qualified_name: &QualifiedName) -> Expr {
|
||||
let Symbol {
|
||||
local_name, spec, ..
|
||||
} = match self.symbol_table.lookup_symbol(&qualified_name.id) {
|
||||
Some(s) => s,
|
||||
//TODO this causes several evaluation tests to fail, figure out what's going on here
|
||||
//None => return Expr::ReductionError(format!("Symbol {:?} not found", sym_name)),
|
||||
None => {
|
||||
let name = qualified_name.components.last().unwrap().clone();
|
||||
return Expr::Sym(name);
|
||||
}
|
||||
};
|
||||
|
||||
match spec {
|
||||
SymbolSpec::RecordConstructor { .. } => Expr::ReductionError(
|
||||
"AST reducer doesn't expect a RecordConstructor here".to_string(),
|
||||
),
|
||||
SymbolSpec::DataConstructor {
|
||||
index,
|
||||
arity,
|
||||
type_name,
|
||||
} => Expr::Constructor {
|
||||
type_name: type_name.clone(),
|
||||
name: local_name.clone(),
|
||||
tag: *index,
|
||||
arity: *arity,
|
||||
},
|
||||
SymbolSpec::Func(_) => Expr::Sym(local_name.clone()),
|
||||
SymbolSpec::Binding => Expr::Sym(local_name.clone()), //TODO not sure if this is right, probably needs to eventually be fqsn
|
||||
}
|
||||
}
|
||||
|
||||
#[allow(clippy::ptr_arg)]
|
||||
fn reduce_lambda(&mut self, params: &[FormalParam], body: &Block) -> Expr {
|
||||
Expr::Func(Func::UserDefined {
|
||||
name: None,
|
||||
params: params.iter().map(|param| param.name.clone()).collect(),
|
||||
body: self.block(body),
|
||||
})
|
||||
}
|
||||
|
||||
fn reduce_named_struct(
|
||||
&mut self,
|
||||
name: &QualifiedName,
|
||||
fields: &[(Rc<String>, Expression)],
|
||||
) -> Expr {
|
||||
let symbol = match self.symbol_table.lookup_symbol(&name.id) {
|
||||
Some(fqsn) => fqsn,
|
||||
None => return Expr::ReductionError(format!("FQSN lookup for name {:?} failed", name)),
|
||||
};
|
||||
|
||||
let (type_name, index, members_from_table) = match &symbol.spec {
|
||||
SymbolSpec::RecordConstructor {
|
||||
members,
|
||||
type_name,
|
||||
index,
|
||||
} => (type_name.clone(), index, members),
|
||||
_ => return Expr::ReductionError("Not a record constructor".to_string()),
|
||||
};
|
||||
|
||||
let arity = members_from_table.len();
|
||||
|
||||
let mut args: Vec<(Rc<String>, Expr)> = fields
|
||||
.iter()
|
||||
.map(|(name, expr)| (name.clone(), self.expression(expr)))
|
||||
.collect();
|
||||
|
||||
args.as_mut_slice()
|
||||
.sort_unstable_by(|(name1, _), (name2, _)| name1.cmp(name2)); //arbitrary - sorting by alphabetical order
|
||||
|
||||
let args = args.into_iter().map(|(_, expr)| expr).collect();
|
||||
|
||||
//TODO make sure this sorting actually works
|
||||
let f = box Expr::Constructor {
|
||||
type_name,
|
||||
name: symbol.local_name.clone(),
|
||||
tag: *index,
|
||||
arity,
|
||||
};
|
||||
Expr::Call { f, args }
|
||||
}
|
||||
|
||||
fn reduce_call_expression(
|
||||
&mut self,
|
||||
func: &Expression,
|
||||
arguments: &[InvocationArgument],
|
||||
) -> Expr {
|
||||
Expr::Call {
|
||||
f: Box::new(self.expression(func)),
|
||||
args: arguments
|
||||
.iter()
|
||||
.map(|arg| self.invocation_argument(arg))
|
||||
.collect(),
|
||||
}
|
||||
}
|
||||
|
||||
fn reduce_if_expression(
|
||||
&mut self,
|
||||
discriminator: Option<&Expression>,
|
||||
body: &IfExpressionBody,
|
||||
) -> Expr {
|
||||
let cond = Box::new(match discriminator {
|
||||
Some(expr) => self.expression(expr),
|
||||
None => return Expr::ReductionError("blank cond if-expr not supported".to_string()),
|
||||
});
|
||||
|
||||
match body {
|
||||
IfExpressionBody::SimpleConditional {
|
||||
then_case,
|
||||
else_case,
|
||||
} => {
|
||||
let then_clause = self.block(then_case);
|
||||
let else_clause = match else_case.as_ref() {
|
||||
None => vec![],
|
||||
Some(stmts) => self.block(stmts),
|
||||
};
|
||||
Expr::Conditional {
|
||||
cond,
|
||||
then_clause,
|
||||
else_clause,
|
||||
}
|
||||
}
|
||||
IfExpressionBody::SimplePatternMatch {
|
||||
pattern,
|
||||
then_case,
|
||||
else_case,
|
||||
} => {
|
||||
let then_clause = self.block(then_case);
|
||||
let else_clause = match else_case.as_ref() {
|
||||
None => vec![],
|
||||
Some(stmts) => self.block(stmts),
|
||||
};
|
||||
|
||||
let alternatives = vec![
|
||||
pattern.to_alternative(then_clause, self.symbol_table),
|
||||
Alternative {
|
||||
matchable: Subpattern {
|
||||
tag: None,
|
||||
subpatterns: vec![],
|
||||
bound_vars: vec![],
|
||||
guard: None,
|
||||
},
|
||||
item: else_clause,
|
||||
},
|
||||
];
|
||||
|
||||
Expr::CaseMatch { cond, alternatives }
|
||||
}
|
||||
IfExpressionBody::CondList(ref condition_arms) => {
|
||||
let mut alternatives = vec![];
|
||||
for arm in condition_arms {
|
||||
match arm.condition {
|
||||
Condition::Expression(ref _expr) => return Expr::UnimplementedSigilValue,
|
||||
Condition::Pattern(ref p) => {
|
||||
let item = self.block(&arm.body);
|
||||
let alt = p.to_alternative(item, self.symbol_table);
|
||||
alternatives.push(alt);
|
||||
}
|
||||
Condition::TruncatedOp(_, _) => return Expr::UnimplementedSigilValue,
|
||||
Condition::Else => return Expr::UnimplementedSigilValue,
|
||||
}
|
||||
}
|
||||
Expr::CaseMatch { cond, alternatives }
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
fn binop(&mut self, binop: &BinOp, lhs: &Expression, rhs: &Expression) -> Expr {
|
||||
let operation = Builtin::from_str(binop.sigil()).ok();
|
||||
match operation {
|
||||
Some(Builtin::Assignment) => Expr::Assign {
|
||||
val: Box::new(self.expression(&*lhs)),
|
||||
expr: Box::new(self.expression(&*rhs)),
|
||||
},
|
||||
Some(op) => {
|
||||
let f = Box::new(Expr::Func(Func::BuiltIn(op)));
|
||||
Expr::Call {
|
||||
f,
|
||||
args: vec![self.expression(&*lhs), self.expression(&*rhs)],
|
||||
}
|
||||
}
|
||||
None => {
|
||||
//TODO handle a user-defined operation
|
||||
Expr::UnimplementedSigilValue
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
fn prefix(&mut self, prefix: &PrefixOp, arg: &Expression) -> Expr {
|
||||
let builtin: Option<Builtin> = TryFrom::try_from(prefix).ok();
|
||||
match builtin {
|
||||
Some(op) => {
|
||||
let f = Box::new(Expr::Func(Func::BuiltIn(op)));
|
||||
Expr::Call {
|
||||
f,
|
||||
args: vec![self.expression(arg)],
|
||||
}
|
||||
}
|
||||
None => {
|
||||
//TODO need this for custom prefix ops
|
||||
Expr::UnimplementedSigilValue
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
fn declaration(&mut self, declaration: &Declaration) -> Stmt {
|
||||
use self::Declaration::*;
|
||||
match declaration {
|
||||
Binding {
|
||||
name,
|
||||
constant,
|
||||
expr,
|
||||
..
|
||||
} => Stmt::Binding {
|
||||
name: name.clone(),
|
||||
constant: *constant,
|
||||
expr: self.expression(expr),
|
||||
},
|
||||
FuncDecl(Signature { name, params, .. }, statements) => Stmt::PreBinding {
|
||||
name: name.clone(),
|
||||
func: Func::UserDefined {
|
||||
name: Some(name.clone()),
|
||||
params: params.iter().map(|param| param.name.clone()).collect(),
|
||||
body: self.block(statements),
|
||||
},
|
||||
},
|
||||
TypeDecl { .. } => Stmt::Noop,
|
||||
TypeAlias { .. } => Stmt::Noop,
|
||||
Interface { .. } => Stmt::Noop,
|
||||
Impl { .. } => Stmt::Expr(Expr::UnimplementedSigilValue),
|
||||
_ => Stmt::Expr(Expr::UnimplementedSigilValue),
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
fn handle_symbol(
|
||||
symbol: Option<&Symbol>,
|
||||
inner_patterns: &[Pattern],
|
||||
symbol_table: &SymbolTable,
|
||||
) -> Subpattern {
|
||||
use self::Pattern::*;
|
||||
let tag = symbol.map(|symbol| match symbol.spec {
|
||||
SymbolSpec::DataConstructor { index, .. } => index,
|
||||
_ => {
|
||||
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 {
|
||||
VarOrName(qualified_name) => {
|
||||
let symbol_exists = symbol_table.lookup_symbol(&qualified_name.id).is_some();
|
||||
if symbol_exists {
|
||||
None
|
||||
} else {
|
||||
let QualifiedName { components, .. } = qualified_name;
|
||||
if components.len() == 1 {
|
||||
Some(components[0].clone())
|
||||
} else {
|
||||
panic!("Bad variable name in pattern");
|
||||
}
|
||||
}
|
||||
}
|
||||
_ => None,
|
||||
})
|
||||
.collect();
|
||||
|
||||
let subpatterns = inner_patterns
|
||||
.iter()
|
||||
.map(|p| match p {
|
||||
Ignored => None,
|
||||
VarOrName(_) => 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 {
|
||||
matchable: Subpattern {
|
||||
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(QualifiedName { components, id }, inner_patterns) => {
|
||||
match symbol_table.lookup_symbol(id) {
|
||||
Some(symbol) => handle_symbol(Some(symbol), inner_patterns, symbol_table),
|
||||
None => panic!("Symbol {:?} not found", components),
|
||||
}
|
||||
}
|
||||
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),
|
||||
VarOrName(QualifiedName { components, id }) => {
|
||||
// if symbol is Some, treat this as a symbol pattern. If it's None, treat it
|
||||
// as a variable.
|
||||
match symbol_table.lookup_symbol(id) {
|
||||
Some(symbol) => handle_symbol(Some(symbol), &[], symbol_table),
|
||||
None => {
|
||||
println!("Components: {:?}", components);
|
||||
let name = if components.len() == 1 {
|
||||
components[0].clone()
|
||||
} else {
|
||||
panic!("check this line of code yo");
|
||||
};
|
||||
Subpattern {
|
||||
tag: None,
|
||||
subpatterns: vec![],
|
||||
guard: None,
|
||||
bound_vars: vec![Some(name)],
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
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(-(*n as i64)),
|
||||
(true, ExpressionKind::FloatLiteral(f)) => Lit::Float(-f),
|
||||
_ => panic!("This should never happen"),
|
||||
});
|
||||
let guard = Some(Expr::Call {
|
||||
f: Box::new(Expr::Func(Func::BuiltIn(Builtin::Equality))),
|
||||
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(Builtin::Equality))),
|
||||
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(Builtin::BooleanNot))),
|
||||
args: vec![Expr::ConditionalTargetSigilValue],
|
||||
}
|
||||
});
|
||||
Subpattern {
|
||||
tag: None,
|
||||
subpatterns: vec![],
|
||||
guard,
|
||||
bound_vars: vec![],
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
92
schala-lang/language/src/reduced_ast/types.rs
Normal file
92
schala-lang/language/src/reduced_ast/types.rs
Normal file
@ -0,0 +1,92 @@
|
||||
#![allow(clippy::enum_variant_names)]
|
||||
|
||||
use crate::builtin::Builtin;
|
||||
use std::rc::Rc;
|
||||
|
||||
#[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),
|
||||
Sym(Rc<String>), //a Sym is anything that can be looked up by name at runtime - i.e. a function or variable address
|
||||
Tuple(Vec<Expr>),
|
||||
Func(Func),
|
||||
Constructor {
|
||||
type_name: Rc<String>,
|
||||
name: Rc<String>,
|
||||
tag: usize,
|
||||
arity: usize, // n.b. arity here is always the value from the symbol table - if it doesn't match what it's being called with, that's an eval error, eval will handle it
|
||||
},
|
||||
Call {
|
||||
f: Box<Expr>,
|
||||
args: Vec<Expr>,
|
||||
},
|
||||
Assign {
|
||||
val: Box<Expr>, //TODO this probably can't be a val
|
||||
expr: Box<Expr>,
|
||||
},
|
||||
Conditional {
|
||||
cond: Box<Expr>,
|
||||
then_clause: Vec<Stmt>,
|
||||
else_clause: Vec<Stmt>,
|
||||
},
|
||||
ConditionalTargetSigilValue,
|
||||
CaseMatch {
|
||||
cond: Box<Expr>,
|
||||
alternatives: Vec<Alternative>,
|
||||
},
|
||||
UnimplementedSigilValue,
|
||||
ReductionError(String),
|
||||
}
|
||||
|
||||
pub type BoundVars = Vec<Option<Rc<String>>>; //remember that order matters here
|
||||
|
||||
#[derive(Debug, Clone)]
|
||||
pub struct Alternative {
|
||||
pub matchable: Subpattern,
|
||||
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(Builtin),
|
||||
UserDefined {
|
||||
name: Option<Rc<String>>,
|
||||
params: Vec<Rc<String>>,
|
||||
body: Vec<Stmt>,
|
||||
},
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user