Implement Nix optlib parser

Units/simple-nix.d/args.ctags

@@ -0,0 +1 @@
+--sort=no

Units/simple-nix.d/expected.tags

@@ -0,0 +1 @@
+this should fail

Units/simple-nix.d/input.nix

@@ -0,0 +1,9 @@
+{ stdenv, fetchgit }:
+
+stdenv.mkDerivation {
+  name = "hello";
+  src = fetchgit {
+    url = "https://example.com";
+    hash = "sha256-AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=";
+  };
+}

docs/news/HEAD.rst

@@ -14,6 +14,8 @@ Parser related changes
 New parsers
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
+* Nix *optlib* by Ben Sima
+
 Changes about parser specific kinds, roles, fields, and extras
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

optlib/nix.c

@@ -0,0 +1,67 @@
+/*
+ * Generated by ./misc/optlib2c from optlib/nix.ctags, Don't edit this manually.
+ */
+#include "general.h"
+#include "parse.h"
+#include "routines.h"
+#include "field.h"
+#include "xtag.h"
+
+
+static void initializeNixParser (const langType language CTAGS_ATTR_UNUSED)
+{
+}
+
+extern parserDefinition* NixParser (void)
+{
+	static const char *const extensions [] = {
+		"nix",
+		NULL
+	};
+
+	static const char *const aliases [] = {
+		NULL
+	};
+
+	static const char *const patterns [] = {
+		NULL
+	};
+
+	static kindDefinition NixKindTable [] = {
+		{
+		  true, 'p', "package", "package definition",
+		},
+		{
+		  true, 'f', "function", "function definition",
+		},
+		{
+		  true, 'a', "attr", "attribute definition",
+		},
+	};
+	static tagRegexTable NixTagRegexTable [] = {
+		{"[p?]name\\s*=\\s*\"(\\w+)\"", "\\1",
+		"p", NULL, NULL, false},
+		{"(\\S+)\\s*=\\s+\\w+:", "\\1",
+		"f", NULL, NULL, false},
+		{"\\s+([a-zA-Z_0-9-]{4,20})\\s*=", "\\1",
+		"a", NULL, NULL, false},
+	};
+
+
+	parserDefinition* const def = parserNew ("Nix");
+
+	def->versionCurrent= 0;
+	def->versionAge    = 0;
+	def->enabled       = true;
+	def->extensions    = extensions;
+	def->patterns      = patterns;
+	def->aliases       = aliases;
+	def->method        = METHOD_NOT_CRAFTED|METHOD_REGEX;
+	def->kindTable     = NixKindTable;
+	def->kindCount     = ARRAY_SIZE(NixKindTable);
+	def->tagRegexTable = NixTagRegexTable;
+	def->tagRegexCount = ARRAY_SIZE(NixTagRegexTable);
+	def->initialize    = initializeNixParser;
+
+	return def;
+}

optlib/nix.ctags

@@ -0,0 +1,40 @@
+#
+#
+#  Copyright (c) 2024, Ben Sima
+#
+#  Author: Ben Sima <ben@bsima.me>
+#
+# 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.
+#
+#
+--langdef=Nix
+--map-Nix=+.nix
+
+# Index packages when we see "name = <tag>" or "pname = <tag>"
+--kinddef-Nix=p,package,package definition
+--regex-Nix=/[p?]name\s*=\s*"(\w+)"/\1/p/
+
+# Functions have args, so look for a : right of the =
+# (This should probably be a multiline regex.)
+--kinddef-Nix=f,function,function definition
+--regex-Nix=/(\S+)\s*=\s+\w+:/\1/f/
+
+# Attrs definitions just have =, but only index if they have >=4 chars,
+# otherwise we get way too many tags. This will also index attr definitions
+# inside nix build files, which is not the most useful when writing nix code,
+# but can be useful when writing packages I guess.
+--kinddef-Nix=a,attr,attribute definition
+--regex-Nix=/\s+([a-zA-Z_0-9-]{4,20})\s*=/\1/a/

source.mak

@@ -241,6 +241,7 @@ OPTLIB2C_INPUT = \
 	optlib/man.ctags			\
 	optlib/meson.ctags			\
 	optlib/mesonOptions.ctags		\
+	optlib/nix.ctags                        \
 	optlib/org.ctags			\
 	optlib/passwd.ctags			\
 	optlib/pkgConfig.ctags			\