Add bat version command to print BAT version

`bat --help` also prints the version, but it's nice to have an explicit
command for this that only prints the version and nothing else.

CHANGELOG.md

@@ -3,6 +3,10 @@
 This file logs the changes that are actually interesting to users (new features,
 changed functionality, fixed bugs).
 
+# Version 1.9 (in development)
+
+- Add `bat version` command to print just the version number and exit.
+
 # Version 1.8 (2021-11-09)
 
 - Compatibility with read-only source files. When packing, file permissions are no longer copied. This means that BAT can modify paths in packed files, even when the source files were read-only.

blender_asset_tracer/cli/__init__.py

@@ -24,7 +24,7 @@ import datetime
 import logging
 import time
 
-from . import blocks, common, pack, list_deps
+from . import blocks, common, pack, list_deps, version
 
 
 def cli_main():
@@ -80,6 +80,7 @@ def cli_main():
     blocks.add_parser(subparsers)
     pack.add_parser(subparsers)
     list_deps.add_parser(subparsers)
+    version.add_parser(subparsers)
 
     args = parser.parse_args()
     config_logging(args)

blender_asset_tracer/cli/version.py

@@ -0,0 +1,32 @@
+# ***** BEGIN GPL LICENSE BLOCK *****
+#
+# 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+#
+# ***** END GPL LICENCE BLOCK *****
+#
+# (c) 2021, Blender Foundation - Sybren A. Stüvel
+"""Print version of BAT and exit."""
+from blender_asset_tracer import __version__
+
+
+def add_parser(subparsers):
+    """Add argparser for this subcommand."""
+
+    parser = subparsers.add_parser("version", help=__doc__)
+    parser.set_defaults(func=cli_version)
+
+
+def cli_version(_):
+    print(__version__)