test/ParseSongFilter: new debug program

Makefile.am

@@ -1862,6 +1862,7 @@ TESTS = $(C_TESTS)
 
 noinst_PROGRAMS = \
 	$(C_TESTS) \
+	test/ParseSongFilter \
 	test/read_conf \
 	test/run_resolver \
 	test/run_input \
@@ -1904,6 +1905,14 @@ if ENABLE_ALSA
 noinst_PROGRAMS += test/read_mixer
 endif
 
+test_ParseSongFilter_LDADD = \
+	$(TAG_LIBS) \
+	$(ICU_LDADD) \
+	libutil.a
+test_ParseSongFilter_SOURCES = \
+	src/SongFilter.cxx \
+	test/ParseSongFilter.cxx
+
 test_read_conf_LDADD = \
 	libconf.a \
 	$(FS_LIBS) \

test/ParseSongFilter.cxx

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2003-2018 The Music Player Daemon Project
+ * http://www.musicpd.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.
+ */
+
+/*
+ * This program is a command line interface to SongFilter::Parse().
+ *
+ */
+
+#include "config.h"
+#include "SongFilter.hxx"
+#include "util/ConstBuffer.hxx"
+#include "util/PrintException.hxx"
+
+#include <stdexcept>
+
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, char **argv)
+try {
+	if (argc < 2) {
+		fprintf(stderr, "Usage: ParseSongFilter FILTER ...\n");
+		return 1;
+	}
+
+	SongFilter filter;
+	filter.Parse(ConstBuffer<const char *>(argv + 1, argc - 1));
+
+	puts(filter.ToExpression().c_str());
+	return EXIT_SUCCESS;
+} catch (...) {
+	PrintException(std::current_exception());
+	return EXIT_FAILURE;
+}