Moved sym lookup logic from eval to ast reducer

schala-lang/language/src/eval.rs

@@ -208,7 +208,10 @@ impl<'a> State<'a> {
       Node::Expr(expr) => match expr {
         literal @ Lit(_) => Ok(Node::Expr(literal)),
         Call { box f, args } => self.call_expression(f, args),
-        Sym(v) => self.handle_sym(v),
+        Sym(name) => Ok(match self.values.lookup(&name) {
+          Some(ValueEntry::Binding { val, .. }) => val.clone(),
+          None => return Err(format!("Could not look up symbol {}", name))
+        }),
         Constructor { arity, ref name, tag, .. } if arity == 0 => Ok(Node::PrimObject { name: name.clone(), tag, items: vec![] }),
         constructor @ Constructor { .. } => Ok(Node::Expr(constructor)),
         func @ Func(_) => Ok(Node::Expr(func)),
@@ -452,46 +455,4 @@ impl<'a> State<'a> {
     }
     Err(format!("{:?} failed pattern match", cond))
   }
-
-  //TODO if I don't need to lookup by name here...
-  fn handle_sym(&mut self, name: Rc<String>) -> EvalResult<Node> {
-    use self::ValueEntry::*;
-    use self::Func::*;
-    //TODO add a layer of indirection here to talk to the symbol table first, and only then look up
-    //in the values table
-
-    let symbol_table = self.symbol_table_handle.borrow();
-    let value = symbol_table.lookup_by_fqsn(&fqsn!(name ; tr));
-    Ok(match value {
-      Some(Symbol { local_name, spec, .. }) => match spec {
-        //TODO I'll need this type_name later to do a table lookup
-        SymbolSpec::DataConstructor { type_name: _type_name, type_args, .. } => {
-          if type_args.len() == 0 {
-            Node::PrimObject { name: local_name.clone(), tag: 0, items: vec![] }
-          } else {
-            return Err(format!("This data constructor thing not done"))
-          }
-        },
-        SymbolSpec::Func(_) => match self.values.lookup(&name) {
-          Some(Binding { val: Node::Expr(Expr::Func(UserDefined { name, params, body })), .. }) => {
-            Node::Expr(Expr::Func(UserDefined { name: name.clone(), params: params.clone(), body: body.clone() }))
-          },
-          _ => unreachable!(),
-        },
-        SymbolSpec::RecordConstructor { .. } => return Err(format!("This shouldn't be a record!")),
-        SymbolSpec::Binding => match self.values.lookup(&name) {
-          Some(Binding { val, .. }) => val.clone(),
-          None => return Err(format!("Symbol {} exists in symbol table but not in evaluator table", name))
-        }
-        SymbolSpec::Type { name } => return Err(format!("Symbol {} not in scope", name)),
-      },
-      //TODO ideally this should be returning a runtime error if this is ever None, but it's not
-      //handling all bindings correctly yet
-      //None => return Err(format!("Couldn't find value {}", name)),
-      None => match self.values.lookup(&name) {
-        Some(Binding { val, .. }) => val.clone(),
-        None => return Err(format!("Couldn't find value {}", name)),
-      }
-    })
-  }
 }

schala-lang/language/src/reduced_ast.rs

@@ -42,9 +42,9 @@ pub enum Stmt {
 pub enum Expr {
   Unit,
   Lit(Lit),
+  Sym(Rc<String>), //a Sym is anything that can be looked up by name at runtime - i.e. a function or variable address
   Tuple(Vec<Expr>),
   Func(Func),
-  Sym(Rc<String>),
   Constructor {
     type_name: Rc<String>,
     name: Rc<String>,
@@ -56,7 +56,7 @@ pub enum Expr {
     args: Vec<Expr>,
   },
   Assign {
-    val: Box<Expr>,
+    val: Box<Expr>, //TODO this probably can't be a val
     expr: Box<Expr>,
   },
   Conditional {
@@ -196,15 +196,16 @@ impl<'a> Reducer<'a> {
     };
 
     match spec {
-      SymbolSpec::DataConstructor { index, type_args, type_name} => {
-        Expr::Constructor {
-          type_name: type_name.clone(),
-          name: name.clone(),
-          tag: index.clone(),
-          arity: type_args.len(),
-        }
+      SymbolSpec::RecordConstructor { .. } => Expr::ReductionError(format!("AST reducer doesn't expect a RecordConstructor here")),
+      SymbolSpec::DataConstructor { index, type_args, type_name } => Expr::Constructor {
+        type_name: type_name.clone(),
+        name: name.clone(),
+        tag: index.clone(),
+        arity: type_args.len(),
       },
-      _ => Expr::Sym(name.clone()),
+      SymbolSpec::Func(_) => Expr::Sym(local_name.clone()),
+      SymbolSpec::Binding => Expr::Sym(local_name.clone()), //TODO not sure if this is right, probably needs to eventually be fqsn
+      SymbolSpec::Type { .. } => Expr::ReductionError("AST reducer doesnt expect a type here".to_string())
     }
   }