adding command line tool for checking an regex

Makefile

@@ -3,7 +3,7 @@ CC = gcc
 LDFLAGS = -lxml2 -lcurl -lpcre
 CFLAGS = -g -Wall -O2 -I/usr/include/libxml2
 
-PROGRAMS = dlight dlight-compile dlight-read-config
+PROGRAMS = dlight dlight-compile dlight-read-config dlight-filter-check
 
 all : $(PROGRAMS)
 
@@ -13,6 +13,7 @@ install : $(PROGRAMS)
 dlight : dlight.o env.o http.o rss.o lockfile.o filter.o cconf.o dlhist.o error.o
 dlight-compile : compile.o env.o lockfile.o filter.o cconf.o error.o
 dlight-read-config : read-config.o env.o cconf.o error.o
+dlight-filter-check: filter-check.o filter.o error.o
 
 dlight-% : %.o
 	$(CC) $(LDFLAGS) -o $@ $^

filter-check.c

@@ -0,0 +1,40 @@
+/* filter-check.c
+ *
+ *   Copyright (C) 2011       Henrik Hautakoski <henrik@fiktivkod.org>
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ *   MA 02110-1301, USA.
+ */
+#include <stdio.h>
+#include "error.h"
+#include "filter.h"
+
+const char *usagestr = "dlight-filter-check <pattern> <subject>";
+
+int main(int argc, char **argv) {
+
+	if (argc < 3)
+		usage(usagestr);
+
+	if (!filter_check_syntax(argv[1]))
+		return 0;
+
+	if (filter_match(argv[1], argv[2])) {
+		puts("match");
+	} else {
+		puts("nomatch");
+	}
+	return 0;
+}