Python通过正则表达式选取callback的方法

#!/bin/env pythonimport re, sys# Define parser first.def baidu(username):  # Business logic  return "Using parser Baidu. and the user's name is: %s." % usernamedef qzone(uin):  # Business logic  return "Using parser Qzone, and the user's QQ is: %s." % uin# From web.pydef group(seq, size):#{{{  """  Returns an iterator over a series of lists of length size from iterable.    >>> list(group([1,2,3,4], 2))    [[1, 2], [3, 4]]    >>> list(group([1,2,3,4,5], 2))    [[1, 2], [3, 4], [5]]  """  def take(seq, n):    for i in xrange(n):      yield seq.next()  if not hasattr(seq, 'next'):    seq = iter(seq)  while True:    x = list(take(seq, size))    if x:      yield x    else:      break#}}}def parser_init(url,mapping):  for pat, what in group(mapping,2):    result = re.compile('^' + pat + '$').match(url)    if result:      return what, [x for x in result.groups()]  return None, Noneif __name__ == '__main__':  mapping = (      'http://(?:hi|space).baidu.com/([^/]+)(?:/.*)?','baidu',      'http://(/d+).qzone.qq.com(?:/.*)?','qzone',      )  (func, args) = parser_init(sys.argv[1],mapping)  if func:    callback = func    if func in globals():      callback = globals()[func]    if callable(callback):      print callback(*args)  else:    print 'No parser found.';