Add provisions to overload the return type also

src/builtins.c

@@ -44,8 +44,8 @@
 {.name="block!",              .calltype=call, .argc=1, .args={block},  .returns=true, .rettype=block},
 {.name="boolean!",            .calltype=call, .argc=1, .args={boolean},.returns=true, .rettype=boolean},
 
-{.name="first",               .calltype=call, .argc=1, .args={any},      .returns=true, .rettype=any, .overload=true, .overloads={list,string,NIL}},
-{.name="rest",                .calltype=call, .argc=1, .args={any},      .returns=true, .rettype=any, .overload=true, .overloads={list,string,NIL}, .overload_to_return=true},
+{.name="first",               .calltype=call, .argc=1, .args={any},      .returns=true, .rettype=any, .overload=true, .overloads={list,string,NIL}, .overload_returns={any, string, NIL}},
+{.name="rest",                .calltype=call, .argc=1, .args={any},      .returns=true, .rettype=any, .overload=true, .overloads={list,string,NIL}, .overload_returns={list, string, NIL}},
 {.name="push",                .calltype=call, .argc=2, .args={any, list}, .returns=true, .rettype=list},
 {.name="empty?",              .calltype=call, .argc=1, .args={list},      .returns=true, .rettype=boolean},
 {.name="join",                .calltype=call, .argc=2, .args={string, string}, .returns=true, .rettype=string},

src/cognac.c

@@ -291,7 +291,7 @@ func_t* make_func(ast_list_t* tree, char* name)
 	func->has_regs = false;
 	func->overload = false;
 	func->overloaded_to = any;
-	func->overload_to_return = false;
+	func->overload_returns[0] = NIL;
 	func->builtin = false;
 	func->name = name;
 	func->locals = NULL;
@@ -1931,8 +1931,8 @@ bool add_var_types_forwards(module_t* mod)
 										for ( val_list_t* vv = new_fn->args ; vv ; vv = vv->next )
 											if (vv->val == v->val) vv->val = make_value(t, v->val->source);
 										new_fn->overloaded_to = t;
-										if (fn->overload_to_return && new_fn->returns)
-											new_fn->rettype = t;
+										if (fn->overload_returns[0] != NIL && new_fn->returns)
+											new_fn->rettype = fn->overload_returns[i];
 										op->op->func = new_fn;
 										goto end;
 									}
@@ -3467,8 +3467,8 @@ word_list_t* builtins(void)
 		fn->overloaded_to = any;
 		fn->unmangled_name = b[i].name;
 		fn->overload = b[i].overload;
-		fn->overload_to_return = b[i].overload_to_return;
 		if (b[i].overload) memcpy(&fn->overloads, &b[i].overloads, sizeof(b[i].overloads));
+		if (b[i].overload) memcpy(&fn->overload_returns, &b[i].overload_returns, sizeof(b[i].overload_returns));
 		type_t calltype = b[i].calltype;
 		for (int ii = b[i].argc-1 ; ii >= 0 ; --ii)
 			fn->args = push_val(make_value(b[i].args[ii], NULL), fn->args);

src/cognac.h

@@ -121,8 +121,8 @@ struct _builtin_t
 	val_type_t storagetype;
 	val_type_t rettype;
 	val_type_t overloads[10];
+	val_type_t overload_returns[10];
 	bool overload;
-	bool overload_to_return;
 	//val_type_t checks;
 };
 
@@ -197,8 +197,8 @@ struct _func_t
 	size_t argc;
 	char* name;
 	val_type_t overloads[10];
+	val_type_t overload_returns[10];
 	val_type_t overloaded_to;
-	bool overload_to_return;
 	bool overload;
 	bool returns;
 	bool stack;

src/runtime.h

@@ -292,7 +292,7 @@ static BOOLEAN ___ioQ(ANY);
 static BOOLEAN ___zeroQ(ANY);
 static ANY ___first(ANY);
 static ANY ___rest(ANY);
-static ANY ___first_STRING(STRING);
+static STRING ___first_STRING(STRING);
 static STRING ___rest_STRING(STRING);
 static ANY ___first_LIST(LIST);
 static LIST ___rest_LIST(LIST);
@@ -1493,10 +1493,10 @@ static LIST ___rest_LIST(LIST lst)
 	return lst->next;
 }
 
-static ANY ___first_STRING(STRING str)
+static STRING ___first_STRING(STRING str)
 {
 	if unlikely(!*str) throw_error("empty string is invalid");
-	return box_STRING(gc_strndup((char*)str, mblen(str, MB_CUR_MAX)));
+	return gc_strndup((char*)str, mblen(str, MB_CUR_MAX));
 }
 
 static STRING ___rest_STRING(STRING str)
@@ -1510,7 +1510,7 @@ static ANY ___first(ANY a)
 	switch(a.type)
 	{
 		case list:   return ___first_LIST(a.list);
-		case string: return ___first_STRING(a.string);
+		case string: return box_STRING(___first_STRING(a.string));
 		default: type_error("string or list", a);
 	}
 }