Python通过正则表达式选取callback的方法

#!/bin/env python
import re,sys
# Define parser first.
def baidu(username):
  # Business logic
  return "Using parser Baidu. and the user's name is: %s." % username
def qzone(uin):
  # Business logic
  return "Using parser Qzone,and the user's QQ is: %s." % uin
# From web.py
def 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([1,4,5],[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,None
if __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.';