From 2da7b3f9a0fc067d7652ac4a8158d7ac0d24c1bb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andrius=20=C5=A0tikonas?= <andrius@stikonas.eu>
Date: Tue, 2 Nov 2021 21:51:38 +0000
Subject: [PATCH] Implement #undef.

---
 cc_macro.c                 | 40 ++++++++++++++++++++++++++++++++++++++
 test/test.answers          | 12 ++++++------
 test/test1000/proof.answer |  2 +-
 3 files changed, 47 insertions(+), 7 deletions(-)

diff --git a/cc_macro.c b/cc_macro.c
index 37626b2..82d010f 100644
--- a/cc_macro.c
+++ b/cc_macro.c
@@ -142,6 +142,36 @@ struct macro_list* lookup_macro(struct token_list* token)
 	return NULL;
 }
 
+void remove_macro(struct token_list* token)
+{
+	struct macro_list* hold = macro_env;
+	struct macro_list* temp;
+
+	/* Deal with the first element */
+	if (match(token->s, hold->symbol)) {
+		macro_env = hold->next;
+		free(hold);
+		return;
+	}
+
+	/* Remove element form the middle of linked list */
+	while (NULL != hold->next)
+	{
+		if (match(token->s, hold->next->symbol))
+		{
+			temp = hold->next;
+			hold->next = hold->next->next;
+			free(temp);
+			return;
+		}
+
+		hold = hold->next;
+	}
+
+	/* nothing to undefine */
+	return;
+}
+
 int macro_expression();
 int macro_variable()
 {
@@ -423,7 +453,13 @@ void handle_define()
 
 		eat_current_token();
 	}
+}
 
+void handle_undef()
+{
+	eat_current_token();
+	remove_macro(macro_token);
+	eat_current_token();
 }
 
 void handle_error()
@@ -576,6 +612,10 @@ void macro_directive()
 	{
 		handle_define();
 	}
+	else if(match("#undef", macro_token->s))
+	{
+		handle_undef();
+	}
 	else if(match("#error", macro_token->s))
 	{
 		handle_error();
diff --git a/test/test.answers b/test/test.answers
index f2705f6..305691a 100644
--- a/test/test.answers
+++ b/test/test.answers
@@ -212,9 +212,9 @@ eb1f6aab09a1a4966f9f49a518d8aa03ca97aa7c46e443871d758a306671a85e  test/results/t
 a2cbfd5f76d3be8049c6737e3fa02f191caf29b6885db006fa23f86e6eacc186  test/results/test0106-knight-posix-binary
 d75e450e2fcdf19df63f9d6a3fe5e032933e57b33f6f06b39a8ed2f3dc759f17  test/results/test0106-riscv64-binary
 473cc504d6cba9eaf648abcf15c83a317ff3f4a7f08f5e8936e3b35b2cc4fbc6  test/results/test0106-x86-binary
-bf1d23078b04a88ad8eeb615a3208f76cf1c2bd4c7070452f887c569ad94b684  test/results/test1000-aarch64-binary
-aeb6d1cbb3616b8e6fc20b195dcc164cc77c835810c1a3c90504c3749f662385  test/results/test1000-amd64-binary
-bb88a105f120d8dc1d34de87114b371363801fbcf4341e510bcb5bcc08e76037  test/results/test1000-armv7l-binary
-85318559fd43f582cefbaf60e4300a59e9589745782b4a9083601152d231fcb6  test/results/test1000-knight-posix-binary
-de7107777e9008b8467c52c5fab7ca91580b4216cf0f6c6737ee538cfb0f2ab3  test/results/test1000-riscv64-binary
-bd66e02f6bfa34187d36116c147f32977c4e3bc34f46df66da4fe828984727e8  test/results/test1000-x86-binary
+163b9e09a19f8cd592af1ad1ff289c985e769df17eb67eea33bf7f9fff140654  test/results/test1000-aarch64-binary
+c8c56324ce5e53e0ce75a0c84db88c39397f79f761b3e2fbec5714b9f058b37c  test/results/test1000-amd64-binary
+19e79a0a80d43e22f1cbd1636985b362273fb2c8bafe27eede2f79aea16b07e5  test/results/test1000-armv7l-binary
+b0c4cb6ba049f97704df3e3694b47364c1302b28e88d87065b27887642ebda76  test/results/test1000-knight-posix-binary
+efe53ac2f7bd3bce3823160232da05af3b8e21e576a38f694272b9dc577a2baa  test/results/test1000-riscv64-binary
+430978cbac169ce8447eb485632698e5b35abcbb49d4d5156a6b66a607117b32  test/results/test1000-x86-binary
diff --git a/test/test1000/proof.answer b/test/test1000/proof.answer
index be43fc5..910e114 100644
--- a/test/test1000/proof.answer
+++ b/test/test1000/proof.answer
@@ -1 +1 @@
-e018a50ea8e2547020473cfdc60066a41cd3793b9d7c164bba5ce7e80a06dd8b  test/test1000/proof
+d9883c3c138fcf943bab6320855cbb30dfa8a7384c6431d4174cb4c137ed644f  test/test1000/proof