#!/usr/bin/env python
     # encoding: utf-8
     #
     # Copyright (c) 2008 Doug Hellmann All rights reserved.
     #
     """
     """
     
     __version__ = "$Id$"
     #end_pymotw_header
     
     import re
     import string
     
     class MyTemplate(string.Template):
         delimiter = '{{'
         pattern = r'''
         \{\{(?:
         (?P<escaped>\{\{)|
         (?P<named>[_a-z][_a-z0-9]*)\}\}|
         (?P<braced>[_a-z][_a-z0-9]*)\}\}|
         (?P<invalid>)
         )
         '''
         
     t = MyTemplate('''
     {{{{
     {{var}}
     ''')
     
     print 'MATCHES:', t.pattern.findall(t.template)
     print 'SUBSTITUTED:', t.safe_substitute(var='replacement')