From 7bbfa1e32537ea0c5e98c0dbb5f77f7bf342118b Mon Sep 17 00:00:00 2001
From: nsfisis <nsfisis@gmail.com>
Date: Sun, 31 Aug 2025 17:07:52 +0900
Subject: feat: support cast expression (any types can be coerced to any types
 for now)

---
 src/parse.c | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

(limited to 'src/parse.c')

diff --git a/src/parse.c b/src/parse.c
index f65c065..467e702 100644
--- a/src/parse.c
+++ b/src/parse.c
@@ -183,6 +183,10 @@ static Token* peek_token(Parser* p) {
     return &p->tokens->data[p->pos];
 }
 
+static Token* peek_token2(Parser* p) {
+    return &p->tokens->data[p->pos + 1];
+}
+
 static Token* next_token(Parser* p) {
     return &p->tokens->data[p->pos++];
 }
@@ -644,13 +648,27 @@ static AstNode* parse_prefix_expr(Parser* p) {
     return parse_postfix_expr(p);
 }
 
+static AstNode* parse_cast_expr(Parser* p) {
+    if (peek_token(p)->kind == TokenKind_paren_l && is_type_token(p, peek_token2(p))) {
+        next_token(p);
+        Type* ty = parse_type(p);
+        expect(p, TokenKind_paren_r);
+
+        // TODO: check whether the original type can be casted to the result type.
+        AstNode* e = parse_cast_expr(p);
+        e->ty = ty;
+        return e;
+    }
+    return parse_prefix_expr(p);
+}
+
 static AstNode* parse_multiplicative_expr(Parser* p) {
-    AstNode* lhs = parse_prefix_expr(p);
+    AstNode* lhs = parse_cast_expr(p);
     while (1) {
         TokenKind op = peek_token(p)->kind;
         if (op == TokenKind_star || op == TokenKind_slash || op == TokenKind_percent) {
             next_token(p);
-            AstNode* rhs = parse_prefix_expr(p);
+            AstNode* rhs = parse_cast_expr(p);
             lhs = ast_new_binary_expr(op, lhs, rhs);
         } else {
             break;
-- 
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