From 36a90bb86667d3675b2babdbd9e262282953f09f Mon Sep 17 00:00:00 2001
From: Dale Weiler <killfieldengine@gmail.com>
Date: Fri, 21 Dec 2012 03:08:21 +0000
Subject: [PATCH] Implemented #warning and #error preprocessor directives,
 they're functionally equivalent to CPPs (supporting both string constant and
 non-string constant versions).  Warnings however are printed with a
 [-Wunused-variable] which isn't correct (TODO: allow systematic changes of -W
 paramaters in relation to warning fields for preprocessor directives.

---
 ftepp.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/ftepp.c b/ftepp.c
index fbe6f96..c7e4273 100644
--- a/ftepp.c
+++ b/ftepp.c
@@ -1010,6 +1010,54 @@ static char *ftepp_include_find(ftepp_t *ftepp, const char *file)
     return filename;
 }
 
+static void ftepp_directive_warning(ftepp_t *ftepp) {
+    char *message = NULL;
+
+    if (!ftepp_skipspace(ftepp))
+        return;
+
+    /* handle the odd non string constant case so it works like C */
+    if (ftepp->token != TOKEN_STRINGCONST) {
+        vec_upload(message, "#warning", 8);
+        ftepp_next(ftepp);
+        while (ftepp->token != TOKEN_EOL) {
+            vec_upload(message, ftepp_tokval(ftepp), strlen(ftepp_tokval(ftepp)));
+            ftepp_next(ftepp);
+        }
+        vec_push(message, '\0');
+        (void)!!ftepp_warn(ftepp, LVL_WARNING, message);
+        vec_free(message);
+        return;
+    }
+
+    unescape  (ftepp_tokval(ftepp), ftepp_tokval(ftepp));
+    (void)!!ftepp_warn(ftepp, LVL_WARNING, "#warning %s", ftepp_tokval(ftepp));
+}
+
+static void ftepp_directive_error(ftepp_t *ftepp) {
+    char *message = NULL;
+
+    if (!ftepp_skipspace(ftepp))
+        return;
+
+    /* handle the odd non string constant case so it works like C */
+    if (ftepp->token != TOKEN_STRINGCONST) {
+        vec_upload(message, "#error", 6);
+        ftepp_next(ftepp);
+        while (ftepp->token != TOKEN_EOL) {
+            vec_upload(message, ftepp_tokval(ftepp), strlen(ftepp_tokval(ftepp)));
+            ftepp_next(ftepp);
+        }
+        vec_push(message, '\0');
+        ftepp_error(ftepp, message);
+        vec_free(message);
+        return;
+    }
+
+    unescape  (ftepp_tokval(ftepp), ftepp_tokval(ftepp));
+    ftepp_error(ftepp, "#error %s", ftepp_tokval(ftepp));
+}
+
 /**
  * Include a file.
  * FIXME: do we need/want a -I option?
@@ -1205,6 +1253,14 @@ static bool ftepp_hash(ftepp_t *ftepp)
                 ftepp_out(ftepp, "#", false);
                 break;
             }
+            else if (!strcmp(ftepp_tokval(ftepp), "warning")) {
+                ftepp_directive_warning(ftepp);
+                break;
+            }
+            else if (!strcmp(ftepp_tokval(ftepp), "error")) {
+                ftepp_directive_error(ftepp);
+                break;
+            }
             else {
                 if (ftepp->output_on) {
                     ftepp_error(ftepp, "unrecognized preprocessor directive: `%s`", ftepp_tokval(ftepp));
-- 
2.39.2