From 4dbe046866a6280cf304c7e0ec6471d872bc8e27 Mon Sep 17 00:00:00 2001
From: Bruce Hill <bruce@bruce-hill.com>
Date: Sun, 12 May 2024 15:18:46 -0400
Subject: Add interface fields

---
 compile.c    | 22 +++++++++++++++-------
 interfaces.c |  2 ++
 typecheck.c  |  2 ++
 types.c      |  7 ++++++-
 4 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/compile.c b/compile.c
index 88c5a0ba..782fc3fe 100644
--- a/compile.c
+++ b/compile.c
@@ -1702,16 +1702,24 @@ CORD compile(env_t *env, ast_t *ast)
                 auto interface = Match(t, InterfaceType);
                 ast_t *impl = call->args->value;
                 type_t *impl_t = get_type(env, impl);
-                if (impl_t->tag != PointerType)
+                if (impl_t->tag != PointerType) {
                     impl = WrapAST(impl, HeapAllocate, impl);
-                CORD c = CORD_all("(", compile_type(env, t), "){", compile(env, impl));
+                    impl_t = Type(PointerType, .pointed=impl_t);
+                }
+                CORD c = CORD_all("({ ", compile_type(env, impl_t), " $impl = ", compile(env, impl), "; (", compile_type(env, t), "){$impl");
                 for (arg_t *field = interface->fields->next; field; field = field->next) {
                     binding_t *b = get_namespace_binding(env, impl, field->name);
-                    if (!b) code_err(ast, "The type %T doesn't have '%s' for the interface %T", impl_t, field->name, t);
-                    // TODO: typecheck implementation!
-                    c = CORD_all(c, ", (void*)", b->code);
+                    if (b) {
+                        // TODO: typecheck implementation!
+                        c = CORD_all(c, ", (void*)", b->code);
+                    } else {
+                        type_t *member_t = get_field_type(impl_t, field->name);
+                        if (!member_t)
+                            code_err(ast, "The type %T doesn't have '%s' for the interface %T", impl_t, field->name, t);
+                        c = CORD_all(c, ", &$impl->", field->name);
+                    }
                 }
-                return CORD_cat(c, "}");
+                return CORD_cat(c, "};})");
             } else if (t->tag == IntType || t->tag == NumType) {
                 // Int/Num constructor:
                 if (!call->args || call->args->next)
@@ -1883,7 +1891,7 @@ CORD compile(env_t *env, ast_t *ast)
             code_err(ast, "There is no '%s' field on tables", f->field);
         }
         case InterfaceType: {
-            code_err(ast, "Interface field access is not yet implemented");
+            return CORD_all("(*(", compile_to_pointer_depth(env, f->fielded, 0, false), ").", f->field, ")");
         }
         case ModuleType: {
             const char *name = Match(value_t, ModuleType)->name;
diff --git a/interfaces.c b/interfaces.c
index a1f1e73f..db587cba 100644
--- a/interfaces.c
+++ b/interfaces.c
@@ -69,6 +69,8 @@ void compile_interface_def(env_t *env, ast_t *ast)
         type_t *field_t = parse_type_ast(env, field_type);
         if (field_t->tag == ClosureType)
             field_t = Match(field_t, ClosureType)->fn;
+        if (field_t->tag != FunctionType)
+            field_t = Type(PointerType, .pointed=field_t);
         CORD decl = compile_declaration(env, field_t, field->name);
         CORD_appendf(&env->code->typecode, "%r%s;\n", decl,
                      field_t->tag == BoolType ? ":1" : "");
diff --git a/typecheck.c b/typecheck.c
index 5e3d005f..fa8e3003 100644
--- a/typecheck.c
+++ b/typecheck.c
@@ -284,6 +284,8 @@ void bind_statement(env_t *env, ast_t *statement)
             if ((field_t->tag == InterfaceType && Match(field_t, InterfaceType)->opaque)
                 || (field_t->tag == EnumType && Match(field_t, EnumType)->opaque))
                 code_err(field_ast->type, "This type is recursive and would create an infinitely sized interface. Try using a pointer.");
+            if (field_t->tag != FunctionType)
+                field_t = Type(PointerType, .pointed=field_t);
             fields = new(arg_t, .name=field_ast->name, .type=field_t, .default_val=field_ast->value, .next=fields);
         }
         REVERSE_LIST(fields);
diff --git a/types.c b/types.c
index fd41bbcc..85060b4c 100644
--- a/types.c
+++ b/types.c
@@ -479,6 +479,8 @@ type_t *get_field_type(type_t *t, const char *field_name)
 {
     t = value_type(t);
     switch (t->tag) {
+    case PointerType:
+        return get_field_type(Match(t, PointerType)->pointed, field_name);
     case StructType: {
         auto struct_t = Match(t, StructType);
         for (arg_t *field = struct_t->fields; field; field = field->next) {
@@ -490,8 +492,11 @@ type_t *get_field_type(type_t *t, const char *field_name)
     case InterfaceType: {
         auto interface = Match(t, InterfaceType);
         for (arg_t *field = interface->fields; field; field = field->next) {
-            if (streq(field->name, field_name))
+            if (streq(field->name, field_name)) {
+                if (field->type->tag == PointerType)
+                    return Match(field->type, PointerType)->pointed;
                 return field->type;
+            }
         }
         return NULL;
     }
-- 
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