From d9eca8ffb39b017e6817d292cb47819e926c72ea Mon Sep 17 00:00:00 2001
From: greg <greg.shuflin@protonmail.com>
Date: Mon, 12 Aug 2019 11:18:03 -0700
Subject: [PATCH] Handle records more properly in symbol table

---
 schala-lang/language/src/symbol_table.rs | 35 ++++++++++++++++++------
 1 file changed, 26 insertions(+), 9 deletions(-)

diff --git a/schala-lang/language/src/symbol_table.rs b/schala-lang/language/src/symbol_table.rs
index b06edf0..c2a83b9 100644
--- a/schala-lang/language/src/symbol_table.rs
+++ b/schala-lang/language/src/symbol_table.rs
@@ -77,11 +77,12 @@ pub enum SymbolSpec {
   Func(Vec<TypeName>),
   DataConstructor {
     index: usize,
-    type_name: Rc<String>,
+    type_name: TypeName,
     type_args: Vec<Rc<String>>,
   },
   RecordConstructor {
-    fields: HashMap<Rc<String>, Rc<String>>
+    members: HashMap<Rc<String>, TypeName>,
+    type_name: TypeName,
   },
   Binding
 }
@@ -92,7 +93,7 @@ impl fmt::Display for SymbolSpec {
     match self {
       Func(type_names) => write!(f, "Func({:?})", type_names),
       DataConstructor { index, type_name, type_args } => write!(f, "DataConstructor(idx: {})({:?} -> {})", index, type_args, type_name),
-      RecordConstructor { fields: _fields } => write!(f, "RecordConstructor( <fields> )"),
+      RecordConstructor { type_name, ..} => write!(f, "RecordConstructor(<members> -> {})", type_name),
       Binding => write!(f, "Binding"),
     }
   }
@@ -180,7 +181,7 @@ impl SymbolTable {
   fn add_type_decl(&mut self, type_name: &TypeSingletonName, body: &TypeBody, _mutable: &bool, scope_name_stack: &mut Vec<ScopeSegment>) -> Result<(), String> {
     use crate::ast::{TypeIdentifier, Variant};
     let TypeBody(variants) = body;
-    let TypeSingletonName { name, .. } = type_name;
+    let ref type_name = type_name.name;
     //scope_name_stack.push(name.clone()); //TODO adding this makes variants scoped under their
     //type name and breaks a lot of things - don't add it until importing names works
     //TODO figure out why _params isn't being used here
@@ -189,28 +190,44 @@ impl SymbolTable {
         Variant::UnitStruct(variant_name) => {
           let spec = SymbolSpec::DataConstructor {
             index,
-            type_name: name.clone(),
+            type_name: type_name.clone(),
             type_args: vec![],
           };
           self.add_new_symbol(variant_name, scope_name_stack, spec);
         },
         Variant::TupleStruct(variant_name, tuple_members) => {
+          //TODO fix the notion of a tuple type
           let type_args = tuple_members.iter().map(|type_name| match type_name {
             TypeIdentifier::Singleton(TypeSingletonName { name, ..}) => name.clone(),
             TypeIdentifier::Tuple(_) => unimplemented!(),
           }).collect();
           let spec = SymbolSpec::DataConstructor {
             index,
-            type_name: name.clone(),
+            type_name: type_name.clone(),
             type_args
           };
           self.add_new_symbol(variant_name, scope_name_stack, spec);
         },
         //TODO if there is only one variant, and it is a record, it doesn't need to have an
         //explicit name
-        Variant::Record { name, members: _members } => {
-          let fields = HashMap::new();
-          let spec = SymbolSpec::RecordConstructor { fields };
+        Variant::Record { name, members: defined_members } => {
+          let mut members = HashMap::new();
+          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));
+          }
+          let spec = SymbolSpec::RecordConstructor { type_name: type_name.clone(), members };
           self.add_new_symbol(name, scope_name_stack, spec);
         },
       }