Unify u32-based identifiers into common code

Create a new type Id<T> paramaterized by whatever specific class of IDs
is relevant to a domain; create stores and macros to support this; and
repace the existing Id types.

rustfmt.toml

@@ -4,4 +4,5 @@ use_small_heuristics = "max"
 imports_indent = "block"
 imports_granularity = "crate"
 group_imports = "stdexternalcrate"
-
+match_arm_blocks = false
+where_single_line = true

schala-lang/language/src/ast/mod.rs

@@ -2,7 +2,6 @@
 #![allow(clippy::enum_variant_names)]
 
 use std::rc::Rc;
-use std::fmt;
 use std::convert::{AsRef, From};
 
 mod visitor;
@@ -13,41 +12,19 @@ pub use visitor::*;
 
 use crate::derivative::Derivative;
 use crate::tokenizing::Location;
+use crate::identifier::{Id, define_id_kind};
 
-/// An abstract identifier for an AST node. Note that
-/// the u32 index limits the size of an AST to 2^32 nodes.
-#[derive(Debug, PartialEq, Eq, Hash, Clone, Default)]
-pub struct ItemId {
-  pub idx: u32,
+define_id_kind!(ASTItem);
+
+/*
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, Default)]
+pub struct ASTItem;
+impl IdKind for ASTItem {
+    fn tag() -> &'static str { "ASTItem" }
 }
+*/
 
-impl ItemId {
-  fn new(n: u32) -> ItemId {
-    ItemId { idx: n }
-  }
-}
-
-impl fmt::Display for ItemId {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-    write!(f, "ItemId:{}", self.idx)
-  }
-}
-
-pub struct ItemIdStore {
-  last_idx: u32
-}
-
-impl ItemIdStore {
-  pub fn new() -> ItemIdStore {
-    ItemIdStore { last_idx: 0 }
-  }
-
-  pub fn fresh(&mut self) -> ItemId {
-    let idx = self.last_idx;
-    self.last_idx += 1;
-    ItemId::new(idx)
-  }
-}
+pub type ItemId = Id<ASTItem>;
 
 #[derive(Derivative, Debug)]
 #[derivative(PartialEq)]

schala-lang/language/src/identifier.rs

@@ -0,0 +1,74 @@
+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())
+    }
+}
+
+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/language/src/lib.rs

@@ -23,10 +23,10 @@ mod tokenizing;
 mod symbol_table;
 mod builtin;
 mod error;
-//mod eval;
-//mod reduced_ast;
 mod reduced_ir;
 mod tree_walk_eval;
+#[macro_use]
+mod identifier;
 
 mod schala;
 

schala-lang/language/src/parsing/mod.rs

@@ -170,6 +170,7 @@ use crate::tokenizing::TokenKind::*;
 use crate::tokenizing::Location;
 
 use crate::ast::*;
+use crate::identifier::IdStore;
 
 /// Represents a parsing error
 #[derive(Debug)]
@@ -201,7 +202,7 @@ pub struct Parser {
   parse_record: Vec<ParseRecord>,
   parse_level: u32,
   restrictions: ParserRestrictions,
-  id_store: ItemIdStore,
+  id_store: IdStore<ASTItem>,
 }
 
 
@@ -252,7 +253,7 @@ impl Parser {
       parse_record: vec![],
       parse_level: 0,
       restrictions: ParserRestrictions { no_struct_literal: false },
-      id_store: ItemIdStore::new(),
+      id_store: IdStore::new(),
     }
   }
 

schala-lang/language/src/symbol_table/mod.rs

@@ -14,42 +14,10 @@ mod resolver;
 mod symbol_trie;
 use symbol_trie::SymbolTrie;
 mod test;
+use crate::identifier::{Id, IdStore, define_id_kind};
 
-
-//TODO parameterize different types of ID
-/// ID used for definitions
-#[derive(Debug, PartialEq, Eq, Hash, Clone, Default)]
-pub struct DefId {
-  idx: u32,
-}
-
-impl DefId {
-  pub fn as_u32(&self) -> u32 {
-      self.idx
-  }
-}
-
-impl fmt::Display for DefId {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-    write!(f, "DefId:{}", self.idx)
-  }
-}
-
-pub struct DefIdStore {
-  last_idx: u32
-}
-
-impl DefIdStore {
-  pub fn new() -> Self {
-    Self { last_idx: 0 }
-  }
-
-  pub fn fresh(&mut self) -> DefId {
-    let idx = self.last_idx;
-    self.last_idx += 1;
-    DefId { idx }
-  }
-}
+define_id_kind!(DefItem);
+pub type DefId = Id<DefItem>;
 
 /// Fully-qualified symbol name
 #[derive(Debug, Clone, Eq, PartialEq, Hash, PartialOrd, Ord)]
@@ -170,7 +138,7 @@ impl<K> NameTable<K> {
 //cf. p. 150 or so of Language Implementation Patterns
 pub struct SymbolTable {
 
-    def_id_store: DefIdStore,
+    def_id_store: IdStore<DefItem>,
 
     /// Used for import resolution.
     symbol_trie: SymbolTrie,
@@ -190,7 +158,7 @@ pub struct SymbolTable {
 impl SymbolTable {
     pub fn new() -> SymbolTable {
         SymbolTable {
-            def_id_store: DefIdStore::new(),
+            def_id_store: IdStore::new(),
             symbol_trie: SymbolTrie::new(),
             fq_names: NameTable::new(),
             types: NameTable::new(),