"""Doctests for templates with bracketed placeholders >>> s = 'People of [planet], take us to your leader.' >>> d = dict(planet='Earth') >>> print convert_template(s) % d People of Earth, take us to your leader. >>> s = 'People of , take us to your leader.' >>> print convert_template(s, '<', '>') % d People of Earth, take us to your leader. """ import re def convert_template(template, opener='[', closer=']'): opener = re.escape(opener) closer = re.escape(closer) pattern = re.compile(opener + '([_A-Za-z][_A-Za-z0-9]*)' + closer) return re.sub(pattern, r'%(\1)s', template.replace('%','%%')) if __name__ == '__main__': import doctest print 'Doctest results: ', doctest.testmod()