1 files changed, 66 insertions, 0 deletions
diff --git a/attoconf/version.py b/attoconf/version.py
new file mode 100644
index 0000000..96db3e5
--- /dev/null
+++ b/attoconf/version.py
@@ -0,0 +1,66 @@
+#   Copyright 2013 Ben Longbons <b.r.longbons@gmail.com>
+#
+#   This file is part of attoconf.
+#
+#   attoconf 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 3 of the License, or
+#   (at your option) any later version.
+#
+#   attoconf 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 attoconf.  If not, see <http://www.gnu.org/licenses/>.
+
+
+
+import sys
+
+from . import _version
+
+if sys.version_info[0] != 3 or sys.version_info[1] < 6:
+    sys.exit('Unsupported Python version: %s\nattoconf requires Python 3.6+' % sys.version)
+
+def require_version(major, minor, patch=0):
+    ''' Check that this is the right version of attoconf, or die trying.
+    '''
+    if major != _version.major:
+        # Once I release attoconf 1.0, I *probably* won't ever
+        # do another major upgrade - that would be difficult to package.
+        sys.exit(
+'''
+This configure script requires a different major version of attoconf.
+Major version changes are rare, and software written against the one
+version is likely to need changes to work with the other version.
+
+Current version: %s
+Minimum required version: %d.%d.%d
+''' % (full_version, major, minor, patch))
+    if minor > _version.minor:
+        # In the interest of good style, it sometimes *should* be rewritten.
+        sys.exit(
+'''
+This configure script requires a newer minor version of attoconf.
+Minor version changes are common, and software written against the one
+minor version will work with all later minor versions.
+
+Current version: %s
+Minimum required version: %d.%d.%d
+''' % (full_version, major, minor, patch))
+    if minor == _version.minor and patch > _version.patch:
+        sys.exit(
+'''
+This configure script requires a newer patch version of attoconf.
+Patch versions are usually not released unless there is a bug in a minor
+version, but it is possible that someone is using experimental features.
+If there is one, upgrade to the latest minor version instead.
+
+Current version: %s
+Minimum required version: %d.%d.%d
+''' % (full_version, major, minor, patch))
+
+part_version = '%d.%d.%d' % (_version.major, _version.minor, _version.patch)
+full_version = 'attoconf %s (%s)' % (part_version, _version.distributor)