Reduce number of tables in symbol table

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

@@ -68,25 +68,39 @@ struct DuplicateName {
   location: Location
 }
 
-//TODO should map to a Spec* type that has Location and Kind of namespace entry
-//tht way I don't need as many tables
-/// Keeps track of what names were used in a given namespace.
-struct NameTable {
-  table: HashMap<FQSN, Location>
+#[derive(Debug)]
+struct NameSpec<K> {
+  location: Location,
+  kind: K
 }
 
-impl NameTable {
+#[derive(Debug)]
+enum NameKind {
+  Module,
+  Function,
+  Binding,
+}
+
+#[derive(Debug)]
+struct TypeKind;
+
+/// 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, location: Location) -> Result<(), DuplicateName> {
+  fn register(&mut self, name: FQSN, spec: NameSpec<K>) -> Result<(), DuplicateName> {
     match self.table.entry(name.clone()) {
       Entry::Occupied(o) => {
-        Err(DuplicateName { prev_name: name, location: *o.get() })
+        Err(DuplicateName { prev_name: name, location: o.get().location })
       },
       Entry::Vacant(v) => {
-        v.insert(location);
+        v.insert(spec);
         Ok(())
       }
     }
@@ -162,9 +176,8 @@ pub struct SymbolTable {
   symbol_path_to_symbol: HashMap<FullyQualifiedSymbolName, Symbol>,
   id_to_fqsn: HashMap<ItemId, FullyQualifiedSymbolName>,
   symbol_trie: SymbolTrie,
-  functions: NameTable, //TODO maybe bindings and functions should be the same table?
-  types: NameTable,
-  bindings: NameTable, //TODO NameTable should be a trie to facilitate quick lookups
+  fq_names: NameTable<NameKind>,
+  types: NameTable<TypeKind>,
 }
 
 impl SymbolTable {
@@ -174,9 +187,8 @@ impl SymbolTable {
       symbol_path_to_symbol: HashMap::new(),
       id_to_fqsn: HashMap::new(),
       symbol_trie: SymbolTrie::new(),
-      functions: NameTable::new(),
+      fq_names: NameTable::new(),
       types: NameTable::new(),
-      bindings: NameTable::new(),
     }
   }
 
@@ -263,7 +275,6 @@ impl SymbolTable {
   /// 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 process_ast(&mut self, ast: &ast::AST) -> Result<(), String> {
-
     let mut scope_stack = vec![Scope::Top];
     self.add_from_scope(ast.statements.as_ref(), &mut scope_stack)
       .map_err(|err| format!("{:?}", err))?;
@@ -279,15 +290,15 @@ impl SymbolTable {
         StatementKind::Declaration(Declaration::FuncSig(signature)) => {
           let fn_name: String = signature.name.as_str().to_owned();
           let fq_function = FQSN::from_scope_stack(scope_stack.as_ref(), fn_name);
-          self.functions.register(fq_function.clone(), location)?;
-          self.types.register(fq_function, location)?;
+          self.fq_names.register(fq_function.clone(), NameSpec { location, kind: NameKind::Function })?;
+          self.types.register(fq_function, NameSpec { location, kind: TypeKind } )?;
         }
         StatementKind::Declaration(Declaration::FuncDecl(signature, body)) => {
           let fn_name: String = signature.name.as_str().to_owned();
           let new_scope = Scope::Name(fn_name.clone());
           let fq_function = FQSN::from_scope_stack(scope_stack.as_ref(), fn_name);
-          self.functions.register(fq_function.clone(), location)?;
-          self.types.register(fq_function, location)?;
+          self.fq_names.register(fq_function.clone(), NameSpec { location, kind: NameKind::Function })?;
+          self.types.register(fq_function, NameSpec { location, kind: TypeKind } )?;
           scope_stack.push(new_scope);
           let output = self.add_from_scope(body.as_ref(), scope_stack);
           scope_stack.pop();
@@ -295,20 +306,20 @@ impl SymbolTable {
         },
         StatementKind::Declaration(Declaration::TypeDecl { name, body, mutable }) => {
           let fq_type = FQSN::from_scope_stack(scope_stack.as_ref(), name.name.as_ref().to_owned());
-          self.types.register(fq_type, location)?;
+          self.types.register(fq_type, NameSpec { location, kind: TypeKind } )?;
           if let Err(errors) = self.add_type_members(name, body, mutable, location, scope_stack) {
             return Err(errors[0].clone());
           }
         },
         StatementKind::Declaration(Declaration::Binding { name, .. }) => {
           let fq_binding = FQSN::from_scope_stack(scope_stack.as_ref(), name.as_str().to_owned());
-          self.bindings.register(fq_binding, location)?;
+          self.fq_names.register(fq_binding, NameSpec { location, kind: NameKind::Binding })?;
         }
         StatementKind::Module(ModuleSpecifier { name, contents }) => {
           let mod_name = name.as_str().to_owned();
           let fq_module = FQSN::from_scope_stack(scope_stack.as_ref(), mod_name.clone());
           let new_scope = Scope::Name(mod_name);
-          self.bindings.register(fq_module, location)?;
+          self.fq_names.register(fq_module, NameSpec { location, kind: NameKind::Module })?;
           scope_stack.push(new_scope);
           let output = self.add_from_scope(contents.as_ref(), scope_stack);
           scope_stack.pop();
@@ -324,7 +335,8 @@ impl SymbolTable {
     let mut errors = vec![];
 
     let mut register = |fqsn: FQSN| {
-      if let Err(err) = self.types.register(fqsn, location) {
+      let spec = NameSpec { location, kind: TypeKind };
+      if let Err(err) = self.types.register(fqsn, spec) {
         errors.push(err);
       }
     };