Doc/lib/required_2.py

   1 import optparse
   2
   3 class Option (optparse.Option):
   4     ATTRS = optparse.Option.ATTRS + ['required']
   5
   6     def _check_required (self):
   7         if self.required and not self.takes_value():
   8             raise OptionError(
   9                 "required flag set for option that doesn't take a value",
  10                  self)
  11
  12     # Make sure _check_required() is called from the constructor!
  13     CHECK_METHODS = optparse.Option.CHECK_METHODS + [_check_required]
  14
  15     def process (self, opt, value, values, parser):
  16         optparse.Option.process(self, opt, value, values, parser)
  17         parser.option_seen[self] = 1
  18
  19
  20 class OptionParser (optparse.OptionParser):
  21
  22     def _init_parsing_state (self):
  23         optparse.OptionParser._init_parsing_state(self)
  24         self.option_seen = {}
  25
  26     def check_values (self, values, args):
  27         for option in self.option_list:
  28             if (isinstance(option, Option) and
  29                 option.required and
  30                 not self.option_seen.has_key(option)):
  31                 self.error("%s not supplied" % option)
  32         return (values, args)
  33
  34
  35 parser = OptionParser(option_list=[
  36     Option("-v", action="count", dest="verbose"),
  37     Option("-f", "--file", required=1)])
  38 (options, args) = parser.parse_args()
  39
  40 print "verbose:", options.verbose
  41 print "file:", options.file