A Python script for swaping source and target language on a Gettext PO file.

poswap.py

#!/usr/bin/env python
# poswap.py
#
# Copyright (C) 2013 Santiago M. Mola
#   Released under the terms of the MIT License.
#
"""
Swaps the source and target language in a Gettext PO file.

Learn more at http://mola.io/2013/09/17/swapping-languages-in-gettext-po-file
"""

import sys

try:
  from translate.storage.pypo import pofile
except ImportError:
  print 'This script requires Translate Toolkit.'
  print 'Download it at http://toolkit.translatehouse.org/'
  sys.exit(1)

if len(sys.argv) != 2:
  print 'USAGE: %s <PO file>' % sys.argv[0]
  sys.exit(1)

filename = sys.argv[1]

po = pofile(open(filename, 'r'))

# Swap every unit, except the first one,
# which should be the gettext header.
for i in po.units[1:]:
  source = i.getsource()
  target = i.gettarget()
  i.setsource(target)
  i.settarget(source)

print po