casting

1 files changed, 23 insertions, 4 deletions

diff --git a/type_checker.c b/type_checker.c
index 86fe63a..0aaa584 100644
--- a/type_checker.c
+++ b/type_checker.c
@@ -81,13 +81,23 @@ static void type_check_decl_list(struct decl_list_node* node) {
         type_check_decl(&node->type, cur);
 }
 
-static const struct type* resolve_assign(struct assign_node* node) {
-    switch (node->lval->type) {
+static bool is_expr_assignable(struct expr_node* node) {
+    switch (node->type) {
         case EXPR_VAR_REF:
-            break;
+            return true;
+        case EXPR_PAREN:
+            const struct expr_list_node* expr_list =
+                node->inner.paren.expr_list;
+            return expr_list->next == NULL
+                && is_expr_assignable(expr_list->expr);
         default:
-            TYPE_PANIC("expression is not assignable");
+            return false;
     }
+}
+
+static const struct type* resolve_assign(struct assign_node* node) {
+    if (!is_expr_assignable(node->lval))
+        TYPE_PANIC("expression is not assignable");
 
     type_check_expr(node->lval);
     type_check_expr(node->rval);
@@ -146,6 +156,12 @@ static const struct type* resolve_paren(struct paren_node* node) {
     return node->expr_list->resolved_type;
 }
 
+static const struct type* resolve_cast(struct cast_node* node) {
+    type_check_expr(node->expr);
+    assert_cast_compatible(&node->type, node->expr->resolved_type);
+    return &node->type;
+}
+
 static void type_check_expr(struct expr_node* node) {
     switch (node->type) {
         case EXPR_INT_LIT:
@@ -178,6 +194,9 @@ static void type_check_expr(struct expr_node* node) {
         case EXPR_PAREN:
             node->resolved_type = resolve_paren(&node->inner.paren);
             break;
+        case EXPR_CAST:
+            node->resolved_type = resolve_cast(&node->inner.cast);
+            break;
     }
 }