Big refactor of symbol table

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

@@ -4,18 +4,15 @@ use std::cell::RefCell;
 use std::rc::Rc;
 
 use crate::symbol_table::SymbolTable;
-use crate::scope_resolution::ScopeResolver;
 use crate::reduced_ast::reduce;
 use crate::eval::State;
 
 fn evaluate_all_outputs(input: &str) -> Vec<Result<String, String>> {
-  let mut ast = crate::util::quick_ast(input);
+  let ast = crate::util::quick_ast(input);
   let symbol_table = Rc::new(RefCell::new(SymbolTable::new()));
   symbol_table.borrow_mut().add_top_level_symbols(&ast).unwrap();
-  {
+
-  let mut scope_resolver = ScopeResolver::new(symbol_table.clone());
+  symbol_table.borrow_mut().process_ast(&ast).unwrap();
-  let _ = scope_resolver.resolve(&mut ast);
-  }
 
   let reduced = reduce(&ast, &symbol_table.borrow());
   let mut state = State::new();

schala-lang/language/src/lib.rs

@@ -25,7 +25,6 @@ mod builtin;
 mod error;
 mod eval;
 mod reduced_ast;
-mod scope_resolution;
 
 mod schala;
 

schala-lang/language/src/reduced_ast.rs

@@ -178,16 +178,7 @@ impl<'a> Reducer<'a> {
   }
 
   fn value(&mut self, qualified_name: &QualifiedName) -> Expr {
-    let sym_name = match self.symbol_table.get_fqsn_from_id(&qualified_name.id) {
+    let Symbol { local_name, spec, .. } = match self.symbol_table.lookup_symbol(&qualified_name.id) {
-      Some(fqsn) => fqsn,
-      None => return Expr::ReductionError(format!("FQSN lookup for Value {:?} failed", qualified_name)),
-    };
-
-    //TODO this probably needs to change
-    let FullyQualifiedSymbolName(ref v) = sym_name;
-    //let name = v.last().unwrap().name.clone();
-
-    let Symbol { local_name, spec, .. } = match self.symbol_table.lookup_by_fqsn(&sym_name) {
       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)),
@@ -220,17 +211,16 @@ impl<'a> Reducer<'a> {
   }
 
   fn reduce_named_struct(&mut self, name: &QualifiedName, fields: &Vec<(Rc<String>, Expression)>) -> Expr {
-    let ref sym_name = match self.symbol_table.get_fqsn_from_id(&name.id) {
+    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 FullyQualifiedSymbolName(ref v) = sym_name;
+    let (type_name, index, members_from_table) = match &symbol.spec {
-    let ref name = v.last().unwrap().name;
+      SymbolSpec::RecordConstructor { members, type_name, index } => (type_name.clone(), index, members),
-    let (type_name, index, members_from_table) = match self.symbol_table.lookup_by_fqsn(&sym_name) {
-      Some(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()
@@ -243,7 +233,7 @@ impl<'a> Reducer<'a> {
     let args = args.into_iter().map(|(_, expr)| expr).collect();
 
     //TODO make sure this sorting actually works
-    let f = box Expr::Constructor { type_name, name: name.clone(), tag: *index, arity, };
+    let f = box Expr::Constructor { type_name, name: symbol.local_name.clone(), tag: *index, arity, };
     Expr::Call { f, args }
   }
 
@@ -387,8 +377,7 @@ fn handle_symbol(symbol: Option<&Symbol>, inner_patterns: &Vec<Pattern>, symbol_
   });
   let bound_vars = inner_patterns.iter().map(|p| match p {
     VarOrName(qualified_name) => {
-      let fqsn = symbol_table.get_fqsn_from_id(&qualified_name.id);
+      let symbol_exists = symbol_table.lookup_symbol(&qualified_name.id).is_some();
-      let symbol_exists = fqsn.and_then(|fqsn| symbol_table.lookup_by_fqsn(&fqsn)).is_some();
       if symbol_exists {
         None
       } else {
@@ -448,12 +437,9 @@ impl Pattern {
     use self::Pattern::*;
     match self {
       TupleStruct(QualifiedName{ components, id }, inner_patterns) => {
-        let fqsn = symbol_table.get_fqsn_from_id(id);
+        match symbol_table.lookup_symbol(id) {
-        match fqsn.and_then(|fqsn| symbol_table.lookup_by_fqsn(&fqsn)) {
           Some(symbol) => handle_symbol(Some(symbol), inner_patterns, symbol_table),
-          None => {
+          None => panic!("Symbol {:?} not found", components)
-            panic!("Symbol {:?} not found", components);
-          }
         }
       },
       TuplePattern(inner_patterns) => handle_symbol(None, inner_patterns, symbol_table),
@@ -463,12 +449,12 @@ impl Pattern {
       Ignored => Subpattern { tag: None, subpatterns: vec![], guard: None, bound_vars: vec![] },
       Literal(lit) => lit.to_subpattern(symbol_table),
       VarOrName(QualifiedName { components, id  }) => {
-        // if fqsn is Some, treat this as a symbol pattern. If it's None, treat it
+        // if symbol is Some, treat this as a symbol pattern. If it's None, treat it
         // as a variable.
-        let fqsn = symbol_table.get_fqsn_from_id(id);
+        match symbol_table.lookup_symbol(id) {
-        match fqsn.as_ref().and_then(|fqsn| symbol_table.lookup_by_fqsn(fqsn)) {
           Some(symbol) => handle_symbol(Some(symbol), &vec![], symbol_table),
           None => {
+            println!("Components: {:?}", components);
             let name = if components.len() == 1 {
               components[0].clone()
             } else {

schala-lang/language/src/schala.rs

@@ -20,7 +20,6 @@ pub struct Schala {
   state: eval::State<'static>,
   /// Keeps track of symbols and scopes
   symbol_table: SymbolTableHandle,
-  resolver: crate::scope_resolution::ScopeResolver<'static>,
   /// Contains information for type-checking
   type_context: typechecking::TypeContext<'static>,
   /// Schala Parser
@@ -45,7 +44,6 @@ impl Schala {
     Schala {
       source_reference: SourceReference::new(),
       symbol_table: symbols.clone(),
-      resolver: crate::scope_resolution::ScopeResolver::new(symbols.clone()),
       state: eval::State::new(),
       type_context: typechecking::TypeContext::new(),
       active_parser: parsing::Parser::new()
@@ -78,18 +76,13 @@ impl Schala {
 
     //2nd stage - parsing
     self.active_parser.add_new_tokens(tokens);
-    let mut ast = self.active_parser.parse()
+    let ast = self.active_parser.parse()
       .map_err(|err| SchalaError::from_parse_error(err, &self.source_reference))?;
 
     // Symbol table
     self.symbol_table.borrow_mut().add_top_level_symbols(&ast)
       .map_err(|err| SchalaError::from_string(err, Stage::Symbols))?;
 
-    // Scope resolution - requires mutating AST
-    self.resolver.resolve(&mut ast)
-      .map_err(|err| SchalaError::from_string(err, Stage::ScopeResolution))?;
-
-
     //WIP - new symbol table
     self.symbol_table.borrow_mut().process_ast(&ast)
       .map_err(|err| SchalaError::from_string(err, Stage::Symbols))?;

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

@@ -9,32 +9,18 @@ use crate::ast;
 use crate::ast::{ItemId, TypeBody, Variant, TypeSingletonName, Signature, Declaration, Statement, StatementKind, ModuleSpecifier};
 use crate::typechecking::TypeName;
 
-
+mod resolver;
-#[allow(unused_macros)]
-macro_rules! fqsn {
-  ( $( $name:expr ; $kind:tt),* ) => {
-    {
-      let mut vec = vec![];
-      $(
-        vec.push(crate::symbol_table::ScopeSegment::new(std::rc::Rc::new($name.to_string())));
-      )*
-      FullyQualifiedSymbolName(vec)
-    }
-  };
-}
-
 mod tables;
 use tables::DeclLocations;
 mod symbol_trie;
 use symbol_trie::SymbolTrie;
 mod test;
 
-
-
 /// Fully-qualified symbol name
 #[derive(Debug, Clone, Eq, PartialEq, Hash, PartialOrd, Ord)]
-struct FQSN {
+pub struct FQSN {
-  scopes: Vec<Scope>,
+  //TODO FQSN's need to be cheaply cloneable
+  scopes: Vec<Scope>, //TODO rename to ScopeSegment
 }
 
 impl FQSN {
@@ -58,7 +44,6 @@ impl FQSN {
 /// One segment within a scope.
 #[derive(Debug, Clone, Eq, PartialEq, Hash, PartialOrd, Ord)]
 enum Scope {
-  Top,
   Name(String)
 }
 
@@ -141,12 +126,21 @@ impl ScopeSegment {
 
 //cf. p. 150 or so of Language Implementation Patterns
 pub struct SymbolTable {
-  decl_locations: DeclLocations,
+  decl_locations: DeclLocations, //TODO delete this
   symbol_path_to_symbol: HashMap<FullyQualifiedSymbolName, Symbol>,
-  id_to_fqsn: HashMap<ItemId, FullyQualifiedSymbolName>,
   symbol_trie: SymbolTrie,
+
+  /// These tables are responsible for preventing duplicate names.
   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 `ItemId`s of instances of use of names to their fully-canonicalized FQSN form.
+  id_to_fqsn: HashMap<ItemId, FQSN>,
+
+  /// 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, Symbol>,
 }
 
 impl SymbolTable {
@@ -154,44 +148,35 @@ impl SymbolTable {
     SymbolTable {
       decl_locations: DeclLocations::new(),
       symbol_path_to_symbol: HashMap::new(),
-      id_to_fqsn: HashMap::new(),
       symbol_trie: SymbolTrie::new(),
+
       fq_names: NameTable::new(),
       types: NameTable::new(),
+      id_to_fqsn: HashMap::new(),
+      fqsn_to_symbol: HashMap::new(),
     }
   }
 
-  pub fn map_id_to_fqsn(&mut self, id: &ItemId, fqsn: FullyQualifiedSymbolName) {
+  pub fn lookup_symbol(&self, id: &ItemId) -> Option<&Symbol> {
-    self.id_to_fqsn.insert(id.clone(), fqsn);
+    let fqsn = self.id_to_fqsn.get(id);
-  }
+    fqsn.and_then(|fqsn| self.fqsn_to_symbol.get(fqsn))
-
-  pub fn get_fqsn_from_id(&self, id: &ItemId) -> Option<FullyQualifiedSymbolName> {
-    self.id_to_fqsn.get(&id).cloned()
   }
 
   fn add_new_symbol(&mut self, local_name: &Rc<String>, scope_path: &Vec<ScopeSegment>, spec: SymbolSpec) {
     let mut vec: Vec<ScopeSegment> = scope_path.clone();
     vec.push(ScopeSegment { name: local_name.clone() });
     let fully_qualified_name = FullyQualifiedSymbolName(vec);
-    let symbol = Symbol { local_name: local_name.clone(), fully_qualified_name: fully_qualified_name.clone(), spec };
+    let symbol = Symbol { local_name: local_name.clone(), /*fully_qualified_name: fully_qualified_name.clone(),*/ spec };
-    self.symbol_trie.insert(&fully_qualified_name);
+    //self.symbol_trie.insert(&fully_qualified_name);
     self.symbol_path_to_symbol.insert(fully_qualified_name, symbol);
   }
-
-  pub fn lookup_by_fqsn(&self, fully_qualified_path: &FullyQualifiedSymbolName) -> Option<&Symbol> {
-    self.symbol_path_to_symbol.get(fully_qualified_path)
-  }
-
-  pub fn lookup_children_of_fqsn(&self, path: &FullyQualifiedSymbolName) -> Vec<FullyQualifiedSymbolName> {
-    self.symbol_trie.get_children(path)
-  }
 }
 
 #[allow(dead_code)]
 #[derive(Debug)]
 pub struct Symbol {
   pub local_name: Rc<String>,
-  fully_qualified_name: FullyQualifiedSymbolName,
+  //fully_qualified_name: FullyQualifiedSymbolName,
   pub spec: SymbolSpec,
 }
 
@@ -206,8 +191,8 @@ pub enum SymbolSpec {
   Func(Vec<TypeName>),
   DataConstructor {
     index: usize,
-    type_name: TypeName,
+    type_name: TypeName, //TODO this eventually needs to be some kind of ID
-    type_args: Vec<Rc<String>>,
+    type_args: Vec<Rc<String>>, //TODO this should be a lookup table into type information, it's not the concern of the symbol table
   },
   RecordConstructor {
     index: usize,
@@ -249,8 +234,11 @@ impl SymbolTable {
     Ok(())
   }
 
-  //TODO does the same thing scope resolution... but maybe I don't need that
+  /// Walks the AST, matching the ID of an identifier used in some expression to
+  /// the corresponding Symbol.
   fn resolve_symbol_ids(&mut self, ast: &ast::AST) -> Result<(), String> {
+    let mut resolver = resolver::Resolver::new(self);
+    resolver.resolve(ast)?;
     Ok(())
   }
 
@@ -259,7 +247,7 @@ 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
   fn populate_name_tables(&mut self, ast: &ast::AST) -> Result<(), String> {
-    let mut scope_stack = vec![Scope::Top];
+    let mut scope_stack = vec![];
     self.add_from_scope(ast.statements.as_ref(), &mut scope_stack)
       .map_err(|err| format!("{:?}", err))?;
     Ok(())
@@ -268,21 +256,32 @@ impl SymbolTable {
   //TODO this should probably return a vector of duplicate name errors
   fn add_from_scope<'a>(&'a mut self, statements: &[Statement], scope_stack: &mut Vec<Scope>) -> Result<(), DuplicateName> {
     for statement in statements {
-      let Statement { id: _, kind, location } = statement;
+      let Statement { id, kind, location } = statement;
       let location = *location;
       match kind {
         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.fq_names.register(fq_function.clone(), NameSpec { location, kind: NameKind::Function })?;
-          self.types.register(fq_function, NameSpec { location, kind: TypeKind } )?;
+          self.types.register(fq_function.clone(), NameSpec { location, kind: TypeKind } )?;
+
+          self.fqsn_to_symbol.insert(fq_function, Symbol {
+            local_name: signature.name.clone(),
+            spec: SymbolSpec::Func(vec![]), //TODO does this inner vec need to exist at all?
+          });
         }
         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.fq_names.register(fq_function.clone(), NameSpec { location, kind: NameKind::Function })?;
-          self.types.register(fq_function, NameSpec { location, kind: TypeKind } )?;
+          self.types.register(fq_function.clone(), NameSpec { location, kind: TypeKind } )?;
+
+          self.fqsn_to_symbol.insert(fq_function, Symbol {
+            local_name: signature.name.clone(),
+            spec: SymbolSpec::Func(vec![]), //TODO does this inner vec need to exist at all?
+          });
+
           scope_stack.push(new_scope);
           let output = self.add_from_scope(body.as_ref(), scope_stack);
           scope_stack.pop();
@@ -291,13 +290,17 @@ 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, NameSpec { location, kind: TypeKind } )?;
-          if let Err(errors) = self.add_type_members(name, body, mutable, location, scope_stack) {
+          if let Err(errors) = self.add_type_members(id, 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.fq_names.register(fq_binding, NameSpec { location, kind: NameKind::Binding })?;
+          self.fq_names.register(fq_binding.clone(), NameSpec { location, kind: NameKind::Binding })?;
+          self.fqsn_to_symbol.insert(fq_binding, Symbol {
+            local_name: name.clone(),
+            spec: SymbolSpec::Binding,
+          });
         }
         StatementKind::Module(ModuleSpecifier { name, contents }) => {
           let mod_name = name.as_str().to_owned();
@@ -315,35 +318,77 @@ impl SymbolTable {
     Ok(())
   }
 
-  fn add_type_members(&mut self, type_name: &TypeSingletonName, type_body: &TypeBody, _mutable: &bool, location: Location, scope_stack: &mut Vec<Scope>) -> Result<(), Vec<DuplicateName>> {
+  fn add_type_members(&mut self, id: &ItemId, type_name: &TypeSingletonName, type_body: &TypeBody, _mutable: &bool, location: Location, scope_stack: &mut Vec<Scope>) -> Result<(), Vec<DuplicateName>> {
     let mut errors = vec![];
 
-    let mut register = |fqsn: FQSN| {
+    let mut register = |fqsn: FQSN, spec: SymbolSpec| {
-      let spec = NameSpec { location, kind: TypeKind };
+      let name_spec = NameSpec { location, kind: TypeKind };
-      if let Err(err) = self.types.register(fqsn, spec) {
+      if let Err(err) = self.types.register(fqsn.clone(), name_spec) {
         errors.push(err);
-      }
+      } else {
+        let local_name = match spec {
+          SymbolSpec::DataConstructor { ref type_name, ..} | SymbolSpec::RecordConstructor { ref type_name, .. } => type_name.clone(),
+          _ => panic!("This should never happen"),
+        };
+        let symbol = Symbol { local_name, spec };
+        self.fqsn_to_symbol.insert(fqsn, symbol);
+      };
     };
 
     let TypeBody(variants) = type_body;
     let new_scope = Scope::Name(type_name.name.as_ref().to_owned());
     scope_stack.push(new_scope);
 
-    for variant in variants {
+    for (index, variant) in variants.iter().enumerate() {
       match variant {
-        Variant::UnitStruct(name) | Variant::TupleStruct(name, _) => {
+        Variant::UnitStruct(name) => {
           let fq_name = FQSN::from_scope_stack(scope_stack.as_ref(), name.as_ref().to_owned());
-          register(fq_name);
+          let spec = SymbolSpec::DataConstructor {
+            index,
+            type_name: name.clone(),
+            type_args: vec![],
+          };
+          register(fq_name, spec);
+        },
+        Variant::TupleStruct(name, items) => {
+          let fq_name = FQSN::from_scope_stack(scope_stack.as_ref(), name.as_ref().to_owned());
+          let spec = SymbolSpec::DataConstructor {
+            index,
+            type_name: name.clone(),
+            type_args: items.iter().map(|_| Rc::new("DUMMY_TYPE_ID".to_string())).collect()
+          };
+          register(fq_name, spec);
         },
         Variant::Record { name, members } => {
           let fq_name = FQSN::from_scope_stack(scope_stack.as_ref(), name.as_ref().to_owned());
-          register(fq_name.clone());
+          let spec = SymbolSpec::RecordConstructor {
-          for (field_name, _) in members {
+            index,
-            let fq_field_name = fq_name.extend(field_name.as_str().to_owned());
+            type_name: name.clone(),
-            register(fq_field_name);
+            members: members.iter()
+              .map(|(_, _)| (Rc::new("DUMMY_FIELD".to_string()), Rc::new("DUMMY_TYPE_ID".to_string()))).collect()
+          };
+          register(fq_name, spec);
+          //TODO check for duplicates among struct member definitions
+          /*
+
+          let mut duplicate_member_definitions = Vec::new();
+          for (member_name, member_type) in defined_members {
+            match members.entry(member_name.clone()) {
+              Entry::Occupied(_) => duplicate_member_definitions.push(member_name.clone()),
+              Entry::Vacant(v) => {
+                v.insert(match member_type {
+                  TypeIdentifier::Singleton(TypeSingletonName { name, ..}) => name.clone(),
+                  TypeIdentifier::Tuple(_) => unimplemented!(),
+                });
               }
             }
           }
+          if duplicate_member_definitions.len() != 0 {
+            return Err(format!("Duplicate member(s) in definition of type {}: {:?}", type_name, duplicate_member_definitions));
+          }
+          */
+        }
+      }
     }
 
     scope_stack.pop();
@@ -355,7 +400,6 @@ impl SymbolTable {
     }
   }
 
-
   pub fn add_top_level_symbols(&mut self, ast: &ast::AST) -> Result<(), String> {
     let mut scope_name_stack = Vec::new();
     self.add_symbols_from_scope(&ast.statements, &mut scope_name_stack)

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

@@ -0,0 +1,112 @@
+use std::rc::Rc;
+
+use crate::symbol_table::{SymbolTable, ScopeSegment, FullyQualifiedSymbolName, FQSN, Scope};
+use crate::ast::*;
+use crate::util::ScopeStack;
+
+type FQSNPrefix = Vec<Scope>;
+
+pub struct Resolver<'a> {
+  symbol_table: &'a mut super::SymbolTable,
+  name_scope_stack: ScopeStack<'a, Rc<String>, FQSNPrefix>,
+}
+
+impl<'a> Resolver<'a> {
+  pub fn new(symbol_table: &'a mut SymbolTable) -> Self {
+    let name_scope_stack: ScopeStack<'a, Rc<String>, FQSNPrefix> = ScopeStack::new(None);
+    Self { symbol_table, name_scope_stack }
+  }
+  pub fn resolve(&mut self, ast: &AST) -> Result<(), String> {
+    walk_ast(self, ast);
+    Ok(())
+  }
+
+  fn lookup_name_in_scope(&self, sym_name: &QualifiedName) -> FQSN {
+    let QualifiedName { components, .. } = sym_name;
+    let first_component = &components[0];
+    match self.name_scope_stack.lookup(first_component) {
+      None => {
+        FQSN {
+          scopes: components.iter()
+            .map(|name| Scope::Name(name.as_ref().to_owned()))
+            .collect()
+        }
+      },
+      Some(fqsn_prefix) => {
+        let mut full_name = fqsn_prefix.clone();
+        let rest_of_name: FQSNPrefix = components[1..].iter().map(|name| Scope::Name(name.as_ref().to_owned())).collect();
+        full_name.extend_from_slice(&rest_of_name);
+
+        FQSN {
+          scopes: full_name
+        }
+      }
+    }
+  }
+
+  // This might be a variable or a pattern, depending on whether this symbol
+  // already exists in the table.
+  fn qualified_name_in_pattern(&mut self, qualified_name: &QualifiedName) {
+    let fqsn = self.lookup_name_in_scope(qualified_name);
+    if self.symbol_table.fqsn_to_symbol.get(&fqsn).is_some() {
+      self.symbol_table.id_to_fqsn.insert(qualified_name.id.clone(), fqsn); //TODO maybe set this to an explicit value if none?
+    }
+  }
+}
+
+impl<'a> ASTVisitor for Resolver<'a> {
+  //TODO need to un-insert these - maybe need to rethink visitor
+  fn import(&mut self, import_spec: &ImportSpecifier) {
+    let ImportSpecifier { ref path_components, ref imported_names, .. } = &import_spec;
+    match imported_names {
+      ImportedNames::All => {
+        let prefix = FQSN {
+          scopes: path_components.iter().map(|c| Scope::Name(c.as_ref().to_owned())).collect()
+        };
+        let members = self.symbol_table.symbol_trie.get_children(&prefix);
+        for member in members.into_iter() {
+          let local_name = match member.scopes.last().unwrap() {
+            Scope::Name(n) => Rc::new(n.clone()),
+            _ => panic!("LOL bad"),
+          };
+          self.name_scope_stack.insert(local_name.clone(), member.scopes);
+        }
+      },
+      ImportedNames::LastOfPath => {
+        let name = path_components.last().unwrap(); //TODO handle better
+        let fqsn_prefix = path_components.iter()
+          .map(|c| Scope::Name(c.as_ref().to_owned()))
+          .collect();
+        self.name_scope_stack.insert(name.clone(), fqsn_prefix);
+      }
+      ImportedNames::List(ref names) => {
+        let fqsn_prefix: FQSNPrefix = path_components.iter()
+          .map(|c| Scope::Name(c.as_ref().to_owned()))
+          .collect();
+        for name in names.iter() {
+          self.name_scope_stack.insert(name.clone(), fqsn_prefix.clone());
+        }
+      }
+    };
+  }
+
+  fn qualified_name(&mut self, qualified_name: &QualifiedName) {
+    let fqsn = self.lookup_name_in_scope(&qualified_name);
+    self.symbol_table.id_to_fqsn.insert(qualified_name.id.clone(), fqsn);
+  }
+
+  fn named_struct(&mut self, qualified_name: &QualifiedName, _fields: &Vec<(Rc<String>, Expression)>) {
+    let fqsn = self.lookup_name_in_scope(&qualified_name);
+    self.symbol_table.id_to_fqsn.insert(qualified_name.id.clone(), fqsn);
+  }
+
+  fn pattern(&mut self, pat: &Pattern) {
+    use Pattern::*;
+    match pat {
+      //TODO I think not handling TuplePattern is an oversight
+      TuplePattern(_) => (),
+      Literal(_) | Ignored => (),
+      TupleStruct(name, _) | Record(name, _) | VarOrName(name) => self.qualified_name_in_pattern(name),
+    };
+  }
+}

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

@@ -1,18 +1,19 @@
 use radix_trie::{Trie, TrieCommon, TrieKey};
-use super::FullyQualifiedSymbolName;
+use super::{Scope, FQSN};
 use std::hash::{Hasher, Hash};
 use std::collections::hash_map::DefaultHasher;
 
 #[derive(Debug)]
-pub struct SymbolTrie(Trie<FullyQualifiedSymbolName, ()>);
+pub struct SymbolTrie(Trie<FQSN, ()>);
 
-impl TrieKey for FullyQualifiedSymbolName {
+impl TrieKey for FQSN {
   fn encode_bytes(&self) -> Vec<u8> {
     let mut hasher = DefaultHasher::new();
     let mut output = vec![];
-    let FullyQualifiedSymbolName(scopes) = self;
+    for segment in self.scopes.iter() {
-    for segment in scopes.iter() {
+      if let Scope::Name(s) = segment {
-      segment.name.as_bytes().hash(&mut hasher);
+        s.as_bytes().hash(&mut hasher);
+      }
       output.extend_from_slice(&hasher.finish().to_be_bytes());
     }
     output
@@ -24,28 +25,44 @@ impl SymbolTrie {
     SymbolTrie(Trie::new())
   }
 
-  pub fn insert(&mut self, fqsn: &FullyQualifiedSymbolName) {
+  pub fn insert(&mut self, fqsn: &FQSN) {
     self.0.insert(fqsn.clone(), ());
   }
 
-  pub fn get_children(&self, fqsn: &FullyQualifiedSymbolName) -> Vec<FullyQualifiedSymbolName> {
+  pub fn get_children(&self, fqsn: &FQSN) -> Vec<FQSN> {
     let subtrie = match self.0.subtrie(fqsn) {
       Some(s) => s,
       None => return vec![]
     };
-    let output: Vec<FullyQualifiedSymbolName> = subtrie.keys().filter(|cur_key| **cur_key != *fqsn).map(|fqsn| fqsn.clone()).collect();
+    let output: Vec<FQSN> = subtrie.keys().filter(|cur_key| **cur_key != *fqsn).map(|fqsn| fqsn.clone()).collect();
     output
   }
 }
 
+#[cfg(test)]
+mod test {
+  use super::*;
+  use crate::symbol_table::{Scope, FQSN};
+
+  fn make_fqsn(strs: &[&str]) -> FQSN {
+    let mut scopes = vec![];
+    for s in strs {
+      scopes.push(Scope::Name(s.to_string()));
+    }
+    FQSN {
+      scopes
+    }
+  }
+
 #[test]
-fn test_trie_insertion() {
+  fn test_trie_insertion() {
     let mut trie = SymbolTrie::new();
 
-  trie.insert(&fqsn!("unrelated"; ty, "thing"; tr));
+    trie.insert(&make_fqsn(&["unrelated","thing"]));
-  trie.insert(&fqsn!("outer"; ty, "inner"; tr));
+    trie.insert(&make_fqsn(&["outer","inner"]));
-  trie.insert(&fqsn!("outer"; ty, "inner"; ty, "still_inner"; tr));
+    trie.insert(&make_fqsn(&["outer","inner", "still_inner"]));
 
-  let children = trie.get_children(&fqsn!("outer"; ty, "inner"; tr));
+    let children = trie.get_children(&make_fqsn(&["outer", "inner"]));
     assert_eq!(children.len(), 1);
+  }
 }

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

@@ -11,7 +11,6 @@ fn add_symbols(src: &str) -> (SymbolTable, Result<(), String>) {
 
 fn make_fqsn(strs: &[&str]) -> FQSN {
   let mut scopes = vec![];
-  scopes.push(Scope::Top);
   for s in strs {
     scopes.push(Scope::Name(s.to_string()));
   }