Lib/getopt.py

   1 # module getopt -- Standard command line processing.
   2
   3 # Function getopt.getopt() has a different interface but provides the
   4 # similar functionality to the Unix getopt() function, with the
   5 # addition of long-option support.  (Long option support added by Lars
   6 # Wirzenius <liw@iki.fi>.)
   7
   8 # It has two required arguments: the first should be argv[1:] (it
   9 # doesn't want the script name), the second the string of option
  10 # letters as passed to Unix getopt() (i.e., a string of allowable
  11 # option letters, with options requiring an argument followed by a
  12 # colon).
  13
  14 # The optional third argument, if present, getopt.getopt works similar
  15 # to the GNU getopt_long function (but optional arguments are not
  16 # supported).  The third argument should be a list of strings that
  17 # name the long options.  If the name ends '=', the argument requires
  18 # an argument.
  19
  20 # It raises the exception getopt.error with a string argument if it
  21 # detects an error.
  22
  23 # It returns two values:
  24 # (1)   a list of pairs (option, option_argument) giving the options in
  25 #       the order in which they were specified.  (I'd use a dictionary
  26 #       but applications may depend on option order or multiple
  27 #       occurrences.)  Boolean options have '' as option_argument.
  28 # (2)   the list of remaining arguments (may be empty).
  29
  30 import string
  31
  32 error = 'getopt.error'
  33
  34 def getopt(args, shortopts, longopts = []):
  35     list = []
  36     longopts = longopts[:]
  37     longopts.sort()
  38     while args and args[0][:1] == '-' and args[0] != '-':
  39         if args[0] == '--':
  40             args = args[1:]
  41             break
  42         if args[0][:2] == '--':
  43             list, args = do_longs(list, args[0][2:], longopts, args[1:])
  44         else:
  45             list, args = do_shorts(list, args[0][1:], shortopts, args[1:])
  46
  47     return list, args
  48
  49 def do_longs(list, opt, longopts, args):
  50     try:
  51         i = string.index(opt, '=')
  52         opt, optarg = opt[:i], opt[i+1:]
  53     except ValueError:
  54         optarg = None
  55
  56     has_arg, opt = long_has_args(opt, longopts)
  57     if has_arg:
  58         if optarg is None:
  59             if not args:
  60                 raise error, 'option --%s requires argument' % opt
  61             optarg, args = args[0], args[1:]
  62     elif optarg:
  63         raise error, 'option --%s must not have an argument' % opt
  64     list.append(('--' + opt, optarg or ''))
  65     return list, args
  66
  67 # Return:
  68 #   has_arg?
  69 #   full option name
  70 def long_has_args(opt, longopts):
  71     optlen = len(opt)
  72     for i in range(len(longopts)):
  73         x, y = longopts[i][:optlen], longopts[i][optlen:]
  74         if opt != x:
  75             continue
  76         if y != '' and y != '=' and i+1 < len(longopts):
  77             if opt == longopts[i+1][:optlen]:
  78                 raise error, 'option --%s not a unique prefix' % opt
  79         if longopts[i][-1:] in ('=', ):
  80             return 1, longopts[i][:-1]
  81         return 0, longopts[i]
  82     raise error, 'option --' + opt + ' not recognized'
  83
  84 def do_shorts(list, optstring, shortopts, args):
  85     while optstring != '':
  86         opt, optstring = optstring[0], optstring[1:]
  87         if short_has_arg(opt, shortopts):
  88             if optstring == '':
  89                 if not args:
  90                     raise error, 'option -%s requires argument' % opt
  91                 optstring, args = args[0], args[1:]
  92             optarg, optstring = optstring, ''
  93         else:
  94             optarg = ''
  95         list.append(('-' + opt, optarg))
  96     return list, args
  97
  98 def short_has_arg(opt, shortopts):
  99     for i in range(len(shortopts)):
 100         if opt == shortopts[i] != ':':
 101             return shortopts[i+1:i+2] == ':'
 102     raise error, 'option -%s not recognized' % opt
 103
 104 if __name__ == '__main__':
 105     import sys
 106     print getopt(sys.argv[1:], "a:b", ["alpha=", "beta"])