1 files changed, 105 insertions, 0 deletions
diff --git a/bin/mtags.c b/bin/mtags.c
new file mode 100644
index 00000000..5c1a057e
--- /dev/null
+++ b/bin/mtags.c
@@ -0,0 +1,105 @@
+/* Copyright (C) 2021  June McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <assert.h>
+#include <err.h>
+#include <regex.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+static void escape(FILE *file, const char *str, size_t len) {
+	for (size_t i = 0; i < len; ++i) {
+		if (str[i] == '\\' || str[i] == '/') {
+			putc('\\', file);
+		}
+		putc(str[i], file);
+	}
+}
+
+int main(int argc, char *argv[]) {
+	int error;
+	bool append = false;
+	const char *path = "tags";
+	for (int opt; 0 < (opt = getopt(argc, argv, "af:"));) {
+		switch (opt) {
+			break; case 'a': append = true;
+			break; case 'f': path = optarg;
+			break; default:  return EX_USAGE;
+		}
+	}
+
+	FILE *tags = fopen(path, (append ? "a" : "w"));
+	if (!tags) err(EX_CANTCREAT, "%s", path);
+
+#ifdef __OpenBSD__
+	error = pledge("stdio rpath", NULL);
+	if (error) err(EX_OSERR, "pledge");
+#endif
+
+	regex_t makeFile, makeLine;
+	regex_t mdocFile, mdocLine;
+	regex_t shFile, shLine;
+	error = 0
+		|| regcomp(&makeFile, "(^|/)Makefile|[.]mk$", REG_EXTENDED | REG_NOSUB)
+		|| regcomp(
+			&makeLine,
+			"^([.][^:$A-Z][^:$[:space:]]*|[^.:$][^:$[:space:]]*):",
+			REG_EXTENDED
+		)
+		|| regcomp(&mdocFile, "[.][1-9]$", REG_EXTENDED | REG_NOSUB)
+		|| regcomp(&mdocLine, "^[.]S[hs] ([^\t\n]+)", REG_EXTENDED)
+		|| regcomp(
+			&shFile, "(^|/)[.](profile|shrc)|[.]sh$", REG_EXTENDED | REG_NOSUB
+		)
+		|| regcomp(&shLine, "^([_[:alnum:]]+)[[:blank:]]*[(][)]", REG_EXTENDED);
+	assert(!error);
+
+	size_t cap = 0;
+	char *buf = NULL;
+	for (int i = optind; i < argc; ++i) {
+		const regex_t *regex;
+		if (!regexec(&makeFile, argv[i], 0, NULL, 0)) {
+			regex = &makeLine;
+		} else if (!regexec(&mdocFile, argv[i], 0, NULL, 0)) {
+			regex = &mdocLine;
+		} else if (!regexec(&shFile, argv[i], 0, NULL, 0)) {
+			regex = &shLine;
+		} else {
+			warnx("skipping unknown file type %s", argv[i]);
+			continue;
+		}
+
+		FILE *file = fopen(argv[i], "r");
+		if (!file) err(EX_NOINPUT, "%s", argv[i]);
+
+		while (0 < getline(&buf, &cap, file)) {
+			regmatch_t match[2];
+			if (regexec(regex, buf, 2, match, 0)) continue;
+			fprintf(
+				tags, "%.*s\t%s\t/^",
+				(int)(match[1].rm_eo - match[1].rm_so), &buf[match[1].rm_so],
+				argv[i]
+			);
+			escape(tags, buf, match[0].rm_eo);
+			fprintf(tags, "/\n");
+		}
+		fclose(file);
+	}
+}