Make symbol names better

Refactor of symbol table to make name lookups
more precise, necessary for struct member lookups

schala-lang/language/src/symbol_table.rs

@@ -11,25 +11,46 @@ use crate::typechecking::TypeName;
 type LineNumber = u32;
 type SymbolTrackTable = HashMap<Rc<String>, LineNumber>;
 
-#[derive(PartialEq, Eq, Hash, Debug)]
-struct PathToSymbol(Vec<Rc<String>>);
+#[derive(PartialEq, Eq, Hash, Debug, Clone)]
+pub struct FullyQualifiedSymbolName(Vec<ScopeSegment>);
 
-#[derive(Debug, Clone)]
-struct ScopeSegment {
-  scope_name: Rc<String>,
-  scope_type: ScopeSegmentKind,
+#[derive(Debug, Clone, Eq, PartialEq, Hash)]
+pub struct ScopeSegment {
+  name: Rc<String>, //TODO maybe this could be a &str, for efficiency?
+  kind: ScopeSegmentKind,
 }
 
-#[derive(Debug, Clone)]
-enum ScopeSegmentKind {
+#[derive(Debug, Clone, Eq, PartialEq, Hash)]
+pub enum ScopeSegmentKind {
   Function,
-  //Type,
+  Type,
+  Terminal,
+}
+
+macro_rules! fqsn {
+  ( $( $name:expr ; $kind:tt),* ) => {
+    {
+      let mut vec = vec![];
+      $(
+        vec.push(ScopeSegment {
+          name: Rc::new($name.to_string()),
+          kind: sym_path_kind!($kind),
+        });
+      )*
+      FullyQualifiedSymbolName(vec)
+    }
+  };
+}
+
+macro_rules! sym_path_kind {
+  (fn) => { ScopeSegmentKind::Function };
+  (ty) => { ScopeSegmentKind::Type };
+  (tr) => { ScopeSegmentKind::Terminal };
 }
 
 //cf. p. 150 or so of Language Implementation Patterns
 pub struct SymbolTable {
-  symbol_path_to_symbol: HashMap<PathToSymbol, Symbol>,
-  type_name_to_symbol: HashMap<Rc<String>, PathToSymbol>
+  symbol_path_to_symbol: HashMap<FullyQualifiedSymbolName, Symbol>,
 }
 
 //TODO add various types of lookups here, maybe multiple hash tables internally?
@@ -37,38 +58,37 @@ impl SymbolTable {
   pub fn new() -> SymbolTable {
     SymbolTable {
       symbol_path_to_symbol: HashMap::new(),
-      type_name_to_symbol: 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.symbol_path_to_symbol.insert(symbol_path, symbol);
+    let mut vec: Vec<ScopeSegment> = scope_path.clone();
+    vec.push(ScopeSegment { name: name.clone(), kind: ScopeSegmentKind::Terminal });
+    let fully_qualified_name = FullyQualifiedSymbolName(vec);
+    let symbol = Symbol { name: name.clone(), fully_qualified_name: fully_qualified_name.clone(), spec };
+    self.symbol_path_to_symbol.insert(fully_qualified_name, symbol);
   }
 
   pub fn lookup_by_name(&self, name: &Rc<String>) -> Option<&Symbol> {
-    self.lookup_by_path(name, &vec![])
+    let vec = vec![
+      ScopeSegment {
+        name: name.clone(),
+        kind: ScopeSegmentKind::Terminal,
+      }
+    ];
+    let symbol_path = FullyQualifiedSymbolName(vec);
+    self.lookup_by_path(&symbol_path)
   }
 
-  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.symbol_path_to_symbol.get(&symbol_path)
-  }
-
-  pub fn lookup_by_type_and_tag(&self, type_name: &Rc<String>, tag: usize) -> Option<&Symbol> {
-    unimplemented!()
+  pub fn lookup_by_path(&self, fully_qualified_path: &FullyQualifiedSymbolName) -> Option<&Symbol> {
+    self.symbol_path_to_symbol.get(fully_qualified_path)
   }
 }
 
 #[derive(Debug)]
 pub struct Symbol {
   pub name: Rc<String>, //TODO does this need to be pub?
-  scopes: Vec<ScopeSegment>,
+  fully_qualified_name: FullyQualifiedSymbolName,
   pub spec: SymbolSpec,
 }
 
@@ -146,8 +166,8 @@ impl SymbolTable {
             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,
+              name: signature.name.clone(),
+              kind: ScopeSegmentKind::Function,
             });
             let output = self.add_symbols_from_scope(body, scope_name_stack);
             let _ = scope_name_stack.pop();
@@ -155,6 +175,7 @@ impl SymbolTable {
           },
           TypeDecl { name, body, mutable } => {
             insert_and_check_duplicate_symbol(&mut seen_identifiers, &name.name)?;
+            //TODO add ScopeSegmentKind::Type here
             self.add_type_decl(name, body, mutable, scope_name_stack)?
           },
           Binding { name, .. } => {
@@ -343,8 +364,8 @@ mod symbol_table_tests {
     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());
+    assert!(symbol_table.lookup_by_path(&fqsn!["a"; tr]).is_some());
+    assert!(symbol_table.lookup_by_path(&fqsn!["some_func"; fn, "a";tr]).is_some());
   }
 
   #[test]
@@ -359,8 +380,8 @@ fn outer_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());
+    assert!(symbol_table.lookup_by_path(&fqsn!("outer_func"; tr)).is_some());
+    assert!(symbol_table.lookup_by_path(&fqsn!("outer_func"; fn, "inner_func"; tr)).is_some());
   }
 
   #[test]
@@ -382,10 +403,10 @@ fn outer_func(x) {
     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());
+    assert!(symbol_table.lookup_by_path(&fqsn!("outer_func"; tr)).is_some());
+    assert!(symbol_table.lookup_by_path(&fqsn!("outer_func"; fn, "inner_func"; tr)).is_some());
+    assert!(symbol_table.lookup_by_path(&fqsn!("outer_func"; fn, "second_inner_func"; tr)).is_some());
+    assert!(symbol_table.lookup_by_path(&fqsn!("outer_func"; fn, "second_inner_func"; fn, "another_inner_func"; tr)).is_some());
   }
 
   #[test]