More symbol-table refactoring

schala-lang/language/src/symbol_table.rs

@@ -4,7 +4,7 @@ use std::fmt;
 use std::fmt::Write;
 
 use crate::ast;
-use crate::ast::Signature;
+use crate::ast::{TypeBody, TypeSingletonName, Signature};
 use crate::typechecking::TypeName;
 
 //cf. p. 150 or so of Language Implementation Patterns
@@ -60,15 +60,47 @@ impl SymbolTable {
   /* note: this adds names for *forward reference* but doesn't actually create any types. solve that problem
    * later */
   pub fn add_top_level_symbols(&mut self, ast: &ast::AST) -> Result<(), String> {
-    use self::ast::{Statement, TypeIdentifier, Variant, TypeSingletonName, TypeBody};
+    use self::ast::Statement;
     use self::ast::Declaration::*;
     for statement in ast.0.iter() {
       let statement = statement.node();
       if let Statement::Declaration(decl) = statement {
         match decl {
-          FuncSig(signature) | FuncDecl(signature, _) => self.add_function_signature(signature),
+          FuncSig(signature) | FuncDecl(signature, _) => self.add_function_signature(signature)?,
+          TypeDecl { name, body, mutable } => self.add_type_decl(name, body, mutable)?,
+          _ => ()
+        }
+      }
+    }
+    Ok(())
+  }
+  pub fn debug_symbol_table(&self) -> String {
+    let mut output = format!("Symbol table\n");
+    for (name, sym) in &self.values {
+      write!(output, "{} -> {}\n", name, sym).unwrap();
+    }
+    output
+  }
+
+  fn add_function_signature(&mut self, signature: &Signature) -> Result<(), String> {
+    let mut local_type_context = LocalTypeContext::new();
+    let types = signature.params.iter().map(|param| match param {
+      (_, Some(type_identifier)) => Rc::new(format!("{:?}", type_identifier)),
+      (_, None) => local_type_context.new_universal_type()
+    }).collect();
+    let spec = SymbolSpec::Func(types);
+    self.values.insert(
+      signature.name.clone(),
+      Symbol { name: signature.name.clone(), spec }
+    );
+    Ok(())
+  }
+
+  fn add_type_decl(&mut self, type_name: &TypeSingletonName, body: &TypeBody, _mutable: &bool) -> Result<(), String> {
+    use crate::ast::{TypeIdentifier, Variant};
+    let TypeBody(variants) = body;
+    let TypeSingletonName { name, .. } = type_name;
     //TODO figure out why _params isn't being used here
-          TypeDecl { name: TypeSingletonName { name, params: _params}, body: TypeBody(variants), mutable: _mutable, } => {
     for (index, var) in variants.iter().enumerate() {
       match var {
         Variant::UnitStruct(variant_name) => {
@@ -92,36 +124,11 @@ impl SymbolTable {
           let symbol = Symbol { name: variant_name.clone(), spec };
           self.values.insert(variant_name.clone(), symbol);
         },
-                e => return Err(format!("{:?} not supported in typing yet", e)),
+        Variant::Record { .. } => return Err(format!("Record types not supported yet")),
-              }
-            }
-          },
-          _ => ()
-        }
       }
     }
     Ok(())
   }
-  pub fn debug_symbol_table(&self) -> String {
-    let mut output = format!("Symbol table\n");
-    for (name, sym) in &self.values {
-      write!(output, "{} -> {}\n", name, sym).unwrap();
-    }
-    output
-  }
-
-  fn add_function_signature(&mut self, signature: &Signature) {
-    let mut local_type_context = LocalTypeContext::new();
-    let types = signature.params.iter().map(|param| match param {
-      (_, Some(type_identifier)) => Rc::new(format!("{:?}", type_identifier)),
-      (_, None) => local_type_context.new_universal_type()
-    }).collect();
-    let spec = SymbolSpec::Func(types);
-    self.values.insert(
-      signature.name.clone(),
-      Symbol { name: signature.name.clone(), spec }
-    );
-  }
 }
 
 struct LocalTypeContext {