From fdda0a1797b8f39d752b64c4b6a7fa8fd2939e7a Mon Sep 17 00:00:00 2001
From: omdxp <omarbelghaouti@gmail.com>
Date: Wed, 4 Sep 2024 12:41:45 +0100
Subject: [PATCH] impl undef

---
 preprocessor/preprocessor.c | 16 ++++++++++++++++
 test.c                      |  3 ++-
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/preprocessor/preprocessor.c b/preprocessor/preprocessor.c
index 9a5e87f..c000478 100644
--- a/preprocessor/preprocessor.c
+++ b/preprocessor/preprocessor.c
@@ -471,6 +471,14 @@ bool preprocessor_token_is_define(struct token *token) {
   return S_EQ(token->sval, "define");
 }
 
+bool preprocessor_token_is_undef(struct token *token) {
+  if (!preprocessor_token_is_preprocessor_keyword(token)) {
+    return false;
+  }
+
+  return S_EQ(token->sval, "undef");
+}
+
 void preprocessor_multi_value_insert_to_vector(struct compile_process *compiler,
                                                struct vector *vec) {
   struct token *value_token = preprocessor_next_token(compiler);
@@ -586,6 +594,11 @@ void preprocessor_handle_definition_token(struct compile_process *compiler) {
                                  preprocessor);
 }
 
+void preprocessor_handle_undef_token(struct compile_process *compiler) {
+  struct token *name_token = preprocessor_next_token(compiler);
+  preprocessor_definition_remove(compiler->preprocessor, name_token->sval);
+}
+
 int preprocessor_handle_hashtag_token(struct compile_process *compiler,
                                       struct token *token) {
   bool is_preprocessed = false;
@@ -593,6 +606,9 @@ int preprocessor_handle_hashtag_token(struct compile_process *compiler,
   if (preprocessor_token_is_define(next_token)) {
     preprocessor_handle_definition_token(compiler);
     is_preprocessed = true;
+  } else if (preprocessor_token_is_undef(next_token)) {
+    preprocessor_handle_undef_token(compiler);
+    is_preprocessed = true;
   }
 
   return is_preprocessed;
diff --git a/test.c b/test.c
index 52170da..83e700c 100644
--- a/test.c
+++ b/test.c
@@ -1 +1,2 @@
-#define ABC(x, y)
+#define ABC 1
+#undef ABC