Rename Scope -> ScopeSegment

Now, an ItemId maps to a DefId, and a DefId maps to
a Symbol in a different table.

TODO.md

@@ -1,10 +1,6 @@
 # Immediate TODOs / General Code Cleanup
 
 
-## Evaluator
-
-* Make the evaluator take ReducedIR items by reference
-
 ## Testing
 
 * Make an automatic (macro-based?) system for numbering compiler errors, this should be every type of error

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

@@ -30,29 +30,29 @@ pub type DefId = Id<DefItem>;
 #[derive(Debug, Clone, Eq, PartialEq, Hash, PartialOrd, Ord)]
 pub struct Fqsn {
     //TODO Fqsn's need to be cheaply cloneable
-    scopes: Vec<Scope>, //TODO rename to ScopeSegment
+    scopes: Vec<ScopeSegment>,
 }
 
 impl Fqsn {
-    fn from_scope_stack(scopes: &[Scope], new_name: Rc<String>) -> Self {
+    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(Scope::Name(new_name));
+        v.push(ScopeSegment::Name(new_name));
         Fqsn { scopes: v }
     }
 
     fn from_strs(strs: &[&str]) -> Fqsn {
         let mut scopes = vec![];
         for s in strs {
-            scopes.push(Scope::Name(Rc::new(s.to_string())));
+            scopes.push(ScopeSegment::Name(Rc::new(s.to_string())));
         }
         Fqsn { scopes }
     }
 
     fn local_name(&self) -> Rc<String> {
-        let Scope::Name(name) = self.scopes.last().unwrap();
+        let ScopeSegment::Name(name) = self.scopes.last().unwrap();
         name.clone()
     }
 }
@@ -72,13 +72,13 @@ impl fmt::Display for Fqsn {
 //TODO eventually this should use ItemId's to avoid String-cloning
 /// One segment within a scope.
 #[derive(Debug, Clone, Eq, PartialEq, Hash, PartialOrd, Ord)]
-enum Scope {
+enum ScopeSegment {
     Name(Rc<String>),
 }
 
-impl fmt::Display for Scope {
+impl fmt::Display for ScopeSegment {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        let Scope::Name(name) = self;
+        let ScopeSegment::Name(name) = self;
         write!(f, "{}", name)
     }
 }
@@ -141,12 +141,7 @@ pub struct SymbolTable {
     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>,
 
-    /// A map of the Fqsn of an AST definition to a Symbol data structure, which contains
-    /// some basic information about what that symbol is and (ideally) references to other tables
-    /// (e.g. typechecking tables) with more information about that symbol.
-    fqsn_to_symbol: HashMap<Fqsn, Rc<Symbol>>,
-
-    id_to_symbol: HashMap<ItemId, Rc<Symbol>>,
+    id_to_def: HashMap<ItemId, DefId>,
     def_to_symbol: HashMap<DefId, Rc<Symbol>>,
 }
 
@@ -158,8 +153,7 @@ impl SymbolTable {
             fq_names: NameTable::new(),
             types: NameTable::new(),
 
-            fqsn_to_symbol: HashMap::new(),
-            id_to_symbol: HashMap::new(),
+            id_to_def: HashMap::new(),
             def_to_symbol: HashMap::new(),
         };
 
@@ -186,7 +180,8 @@ impl SymbolTable {
     }
 
     pub fn lookup_symbol(&self, id: &ItemId) -> Option<&Symbol> {
-        self.id_to_symbol.get(id).map(|s| s.as_ref())
+        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> {
@@ -197,8 +192,12 @@ impl SymbolTable {
     pub fn debug(&self) {
         println!("Symbol table:");
         println!("----------------");
-        for (id, sym) in self.id_to_symbol.iter() {
-            println!("{} => {}", id, sym);
+        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);
+            }
         }
     }
 
@@ -207,9 +206,8 @@ impl SymbolTable {
     fn add_symbol(&mut self, id: &ItemId, fqsn: Fqsn, spec: SymbolSpec) {
         let def_id = self.def_id_store.fresh();
         let symbol = Rc::new(Symbol { fully_qualified_name: fqsn.clone(), spec, def_id });
-        self.symbol_trie.insert(&fqsn);
-        self.fqsn_to_symbol.insert(fqsn, symbol.clone());
-        self.id_to_symbol.insert(*id, symbol.clone());
+        self.symbol_trie.insert(&fqsn, def_id);
+        self.id_to_def.insert(*id, def_id);
         self.def_to_symbol.insert(def_id, symbol);
     }
 
@@ -218,8 +216,7 @@ impl SymbolTable {
         let spec = SymbolSpec::Builtin(builtin);
         let symbol = Rc::new(Symbol { fully_qualified_name: fqsn.clone(), spec, def_id });
 
-        self.symbol_trie.insert(&fqsn);
-        self.fqsn_to_symbol.insert(fqsn, symbol.clone());
+        self.symbol_trie.insert(&fqsn, def_id);
         self.def_to_symbol.insert(def_id, symbol);
     }
 
@@ -331,13 +328,13 @@ impl<'a> SymbolTableRunner<'a> {
     fn add_from_scope(
         &mut self,
         statements: &[Statement],
-        scope_stack: &mut Vec<Scope>,
+        scope_stack: &mut Vec<ScopeSegment>,
         function_scope: bool,
     ) -> Vec<SymbolError> {
         let mut errors = vec![];
 
         for statement in statements {
-            let Statement { id, kind, location } = statement; //TODO I'm not sure if I need to do anything with this ID
+            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);
@@ -345,14 +342,14 @@ impl<'a> SymbolTableRunner<'a> {
                 // If there's an error with a name, don't recurse into subscopes of that name
                 let recursive_errs = match kind {
                     StatementKind::Declaration(Declaration::FuncDecl(signature, body)) => {
-                        let new_scope = Scope::Name(signature.name.clone());
+                        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
                     }
                     StatementKind::Module(ModuleSpecifier { name, contents }) => {
-                        let new_scope = Scope::Name(name.clone());
+                        let new_scope = ScopeSegment::Name(name.clone());
                         scope_stack.push(new_scope);
                         let output = self.add_from_scope(contents.as_ref(), scope_stack, false);
                         scope_stack.pop();
@@ -374,7 +371,7 @@ impl<'a> SymbolTableRunner<'a> {
         id: &ItemId,
         kind: &StatementKind,
         location: Location,
-        scope_stack: &[Scope],
+        scope_stack: &[ScopeSegment],
         function_scope: bool,
     ) -> Result<(), SymbolError> {
         match kind {
@@ -425,7 +422,7 @@ impl<'a> SymbolTableRunner<'a> {
         type_body: &TypeBody,
         _mutable: &bool,
         location: Location,
-        scope_stack: &mut Vec<Scope>,
+        scope_stack: &mut Vec<ScopeSegment>,
     ) -> Vec<SymbolError> {
         let (variants, immediate_variant) = match type_body {
             TypeBody::Variants(variants) => (variants.clone(), false),
@@ -440,7 +437,7 @@ impl<'a> SymbolTableRunner<'a> {
         };
         let type_fqsn = Fqsn::from_scope_stack(scope_stack, type_name.name.clone());
 
-        let new_scope = Scope::Name(type_name.name.clone());
+        let new_scope = ScopeSegment::Name(type_name.name.clone());
         scope_stack.push(new_scope);
 
         // Check for duplicates before registering any types with the TypeContext

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

@@ -2,7 +2,7 @@ use std::rc::Rc;
 
 use crate::{
     ast::*,
-    symbol_table::{Fqsn, Scope, SymbolSpec, SymbolTable},
+    symbol_table::{Fqsn, ScopeSegment, SymbolSpec, SymbolTable},
     util::ScopeStack,
 };
 
@@ -39,51 +39,49 @@ impl<'a> ScopeResolver<'a> {
         walk_ast(self, ast);
     }
 
-    /// This method correctly modifies the id_to_symbol table (ItemId) to have the appropriate
+    /// This method correctly modifies the id_to_def table (ItemId) to have the appropriate
     /// mappings.
     fn lookup_name_in_scope(&mut self, name: &QualifiedName) {
         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
-        //TODO some of these if lets that look into the fqsn_to_symbol table should probaby fail
-        //with an error
         if components.len() == 1 {
-            let local_name: Rc<String> = components[0].clone();
-            let name_type = self.lexical_scopes.lookup(&local_name);
             match name_type {
                 Some(NameType::Import(fqsn)) => {
-                    let symbol = self.symbol_table.fqsn_to_symbol.get(fqsn);
-                    if let Some(symbol) = symbol {
-                        self.symbol_table.id_to_symbol.insert(*id, symbol.clone());
+                    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 = Scope::Name(Rc::new("<local-param>".to_string()));
-                    let fqsn = Fqsn { scopes: vec![lscope, Scope::Name(local_name.clone())] };
+                    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::LocalVariable(item_id)) => {
-                    let symbol = self.symbol_table.id_to_symbol.get(item_id).cloned();
-                    if let Some(symbol) = symbol {
-                        self.symbol_table.id_to_symbol.insert(*id, symbol);
-                    }
-                }
-                None => {
-                    //TODO see if I can reduce this duplicate code
-                    let fqsn = Fqsn { scopes: vec![Scope::Name(local_name.clone())] };
-                    let symbol = self.symbol_table.fqsn_to_symbol.get(&fqsn);
-                    if let Some(symbol) = symbol {
-                        self.symbol_table.id_to_symbol.insert(*id, symbol.clone());
+                    let def_id = self.symbol_table.id_to_def.get(item_id);
+                    if let Some(def_id) = def_id {
+                        let def_id = def_id.clone();
+                        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 {
-            let fqsn = Fqsn { scopes: components.iter().map(|name| Scope::Name(name.clone())).collect() };
-            let symbol = self.symbol_table.fqsn_to_symbol.get(&fqsn);
-            if let Some(symbol) = symbol {
-                self.symbol_table.id_to_symbol.insert(*id, symbol.clone());
+            if let Some(def_id) = def_id {
+                self.symbol_table.id_to_def.insert(*id, def_id);
             }
         }
     }
@@ -98,22 +96,23 @@ impl<'a> ASTVisitor for ScopeResolver<'a> {
         match imported_names {
             ImportedNames::All => {
                 let prefix =
-                    Fqsn { scopes: path_components.iter().map(|c| Scope::Name(c.clone())).collect() };
+                    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.local_name(), NameType::Import(fqsn));
                 }
             }
             ImportedNames::LastOfPath => {
-                let fqsn = Fqsn { scopes: path_components.iter().map(|c| Scope::Name(c.clone())).collect() };
+                let fqsn =
+                    Fqsn { scopes: path_components.iter().map(|c| ScopeSegment::Name(c.clone())).collect() };
                 self.lexical_scopes.insert(fqsn.local_name(), NameType::Import(fqsn));
             }
             ImportedNames::List(ref names) => {
-                let fqsn_prefix: Vec<Scope> =
-                    path_components.iter().map(|c| Scope::Name(c.clone())).collect();
+                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(Scope::Name(name.clone()));
+                    scopes.push(ScopeSegment::Name(name.clone()));
                     let fqsn = Fqsn { scopes };
                     self.lexical_scopes.insert(fqsn.local_name(), NameType::Import(fqsn));
                 }
@@ -148,7 +147,8 @@ impl<'a> ASTVisitor for ScopeResolver<'a> {
             Declaration::Binding { name, .. } => {
                 if let Some(fn_name) = cur_function_name {
                     // We are within a function scope
-                    let fqsn = Fqsn { scopes: vec![Scope::Name(fn_name), Scope::Name(name.clone())] };
+                    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));
                 }
@@ -247,17 +247,18 @@ impl<'a> ASTVisitor for ScopeResolver<'a> {
                 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 = Scope::Name(Rc::new("<local-case-match>".to_string()));
-                    let fqsn = Fqsn { scopes: vec![lscope, Scope::Name(local_name.clone())] };
-                    //let local_name = fqsn.local_name();
+                    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| Scope::Name(name.clone())).collect() };
-                    let symbol = self.symbol_table.fqsn_to_symbol.get(&fqsn);
-                    if let Some(symbol) = symbol {
-                        self.symbol_table.id_to_symbol.insert(*id, symbol.clone());
+                    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);
                     }
                 }
             }

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

@@ -5,17 +5,17 @@ use std::{
 
 use radix_trie::{Trie, TrieCommon, TrieKey};
 
-use super::{Fqsn, Scope};
+use super::{DefId, Fqsn, ScopeSegment};
 
 #[derive(Debug)]
-pub struct SymbolTrie(Trie<Fqsn, ()>);
+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 Scope::Name(s) = segment;
+            let ScopeSegment::Name(s) = segment;
             s.as_bytes().hash(&mut hasher);
             output.extend_from_slice(&hasher.finish().to_be_bytes());
         }
@@ -28,8 +28,12 @@ impl SymbolTrie {
         SymbolTrie(Trie::new())
     }
 
-    pub fn insert(&mut self, fqsn: &Fqsn) {
-        self.0.insert(fqsn.clone(), ());
+    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> {
@@ -53,11 +57,12 @@ mod test {
 
     #[test]
     fn test_trie_insertion() {
+        let id = DefId::default();
         let mut trie = SymbolTrie::new();
 
-        trie.insert(&make_fqsn(&["unrelated", "thing"]));
-        trie.insert(&make_fqsn(&["outer", "inner"]));
-        trie.insert(&make_fqsn(&["outer", "inner", "still_inner"]));
+        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/language/src/tree_walk_eval/evaluator.rs

@@ -56,7 +56,6 @@ impl<'a, 'b> Evaluator<'a, 'b> {
     }
 
     fn block(&mut self, statements: Vec<Statement>) -> EvalResult<Primitive> {
-        //TODO need to handle breaks, returns, etc.
         let mut retval = None;
         for stmt in statements.into_iter() {
             match self.statement(stmt)? {
@@ -69,6 +68,7 @@ impl<'a, 'b> Evaluator<'a, 'b> {
                 break;
             }
             if let Some(_) = self.loop_control {
+                println!("We here?");
                 break;
             }
         }
@@ -142,6 +142,7 @@ impl<'a, 'b> Evaluator<'a, 'b> {
             Expression::Assign { ref lval, box rval } => {
                 let mem = lval.into();
                 let evaluated = self.expression(rval)?;
+                println!("Inserting {:?} into {:?}", evaluated, mem);
                 self.state.environments.insert(mem, MemoryValue::Primitive(evaluated));
                 Primitive::unit()
             }
@@ -206,6 +207,7 @@ impl<'a, 'b> Evaluator<'a, 'b> {
     ) -> 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,
@@ -214,7 +216,10 @@ impl<'a, 'b> Evaluator<'a, 'b> {
             //TODO eventually loops shoudl be able to return something
             let _output = self.block(statements.clone())?;
             match self.loop_control {
-                None | Some(LoopControlFlow::Continue) => (),
+                None => (),
+                Some(LoopControlFlow::Continue) => {
+                    self.loop_control = None;
+                }
                 Some(LoopControlFlow::Break) => {
                     break;
                 }

schala-lang/language/src/tree_walk_eval/test.rs

@@ -467,3 +467,24 @@ 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");
+}