Safe-ish version number list parsing from stdin

version-sort.py

#!/usr/bin/env python
from __future__ import print_function
import sys


def _leloo_multiparse(v):
    parse_fn = None

    try:
        import pkg_resources
        parse_fn = pkg_resources.parse_version
    except ImportError as ex_a:
        try:
            import distutils.version
            parse_fn = distutils.version.StrictVersion
        except ImportError as ex_b:
            sys.stderr.writelines([
                'ERROR: %s\n' % ex_a.message,
                '       %s\n' % ex_b.message,
                '       The sky is falling! No suitable version parsers!\n'])
            sys.exit(1)

    return parse_fn(v)


def sort_versions(x):
    return sorted(x, key=_leloo_multiparse)


if __name__ == '__main__':
    lines = map(str.strip, sys.stdin.readlines())
    print(lines)
    print(sort_versions(lines))