Lib/getopt.py

   1 """Parser for command line options.
   2
   3 This module helps scripts to parse the command line arguments in
   4 sys.argv.  It supports the same conventions as the Unix getopt()
   5 function (including the special meanings of arguments of the form `-'
   6 and `--').  Long options similar to those supported by GNU software
   7 may be used as well via an optional third argument.  This module
   8 provides a single function and an exception:
   9
  10 Gerrit Holl <gerrit@nl.linux.org> moved the string-based exceptions
  11 to class-based exceptions.
  12
  13 getopt() -- Parse command line options
  14 GetoptError -- exception (class) raised with 'opt' attribute, which is the
  15 option involved with the exception.
  16 """
  17
  18 # Long option support added by Lars Wirzenius <liw@iki.fi>.
  19
  20 import string
  21
  22 class GetoptError(Exception):
  23     opt = ''
  24     msg = ''
  25     def __init__(self, *args):
  26         self.args = args
  27         if len(args) == 1:
  28             self.msg = args[0]
  29         elif len(args) == 2:
  30             self.msg = args[0]
  31             self.opt = args[1]
  32
  33     def __str__(self):
  34         return self.msg
  35
  36 error = GetoptError # backward compatibility
  37
  38 def getopt(args, shortopts, longopts = []):
  39     """getopt(args, options[, long_options]) -> opts, args
  40
  41     Parses command line options and parameter list.  args is the
  42     argument list to be parsed, without the leading reference to the
  43     running program.  Typically, this means "sys.argv[1:]".  shortopts
  44     is the string of option letters that the script wants to
  45     recognize, with options that require an argument followed by a
  46     colon (i.e., the same format that Unix getopt() uses).  If
  47     specified, longopts is a list of strings with the names of the
  48     long options which should be supported.  The leading '--'
  49     characters should not be included in the option name.  Options
  50     which require an argument should be followed by an equal sign
  51     ('=').
  52
  53     The return value consists of two elements: the first is a list of
  54     (option, value) pairs; the second is the list of program arguments
  55     left after the option list was stripped (this is a trailing slice
  56     of the first argument).  Each option-and-value pair returned has
  57     the option as its first element, prefixed with a hyphen (e.g.,
  58     '-x'), and the option argument as its second element, or an empty
  59     string if the option has no argument.  The options occur in the
  60     list in the same order in which they were found, thus allowing
  61     multiple occurrences.  Long and short options may be mixed.
  62
  63     """
  64
  65     opts = []
  66     if type(longopts) == type(""):
  67         longopts = [longopts]
  68     else:
  69         longopts = list(longopts)
  70     longopts.sort()
  71     while args and args[0][:1] == '-' and args[0] != '-':
  72         if args[0] == '--':
  73             args = args[1:]
  74             break
  75         if args[0][:2] == '--':
  76             opts, args = do_longs(opts, args[0][2:], longopts, args[1:])
  77         else:
  78             opts, args = do_shorts(opts, args[0][1:], shortopts, args[1:])
  79
  80     return opts, args
  81
  82 def do_longs(opts, opt, longopts, args):
  83     try:
  84         i = string.index(opt, '=')
  85         opt, optarg = opt[:i], opt[i+1:]
  86     except ValueError:
  87         optarg = None
  88
  89     has_arg, opt = long_has_args(opt, longopts)
  90     if has_arg:
  91         if optarg is None:
  92             if not args:
  93                 raise GetoptError('option --%s requires argument' % opt, opt)
  94             optarg, args = args[0], args[1:]
  95     elif optarg:
  96         raise GetoptError('option --%s must not have an argument' % opt, opt)
  97     opts.append(('--' + opt, optarg or ''))
  98     return opts, args
  99
 100 # Return:
 101 #   has_arg?
 102 #   full option name
 103 def long_has_args(opt, longopts):
 104     optlen = len(opt)
 105     for i in range(len(longopts)):
 106         x, y = longopts[i][:optlen], longopts[i][optlen:]
 107         if opt != x:
 108             continue
 109         if y != '' and y != '=' and i+1 < len(longopts):
 110             if opt == longopts[i+1][:optlen]:
 111                 raise GetoptError('option --%s not a unique prefix' % opt, opt)
 112         if longopts[i][-1:] in ('=', ):
 113             return 1, longopts[i][:-1]
 114         return 0, longopts[i]
 115     raise GetoptError('option --%s not recognized' % opt, opt)
 116
 117 def do_shorts(opts, optstring, shortopts, args):
 118     while optstring != '':
 119         opt, optstring = optstring[0], optstring[1:]
 120         if short_has_arg(opt, shortopts):
 121             if optstring == '':
 122                 if not args:
 123                     raise GetoptError('option -%s requires argument' % opt, opt)
 124                 optstring, args = args[0], args[1:]
 125             optarg, optstring = optstring, ''
 126         else:
 127             optarg = ''
 128         opts.append(('-' + opt, optarg))
 129     return opts, args
 130
 131 def short_has_arg(opt, shortopts):
 132     for i in range(len(shortopts)):
 133         if opt == shortopts[i] != ':':
 134             return shortopts[i+1:i+2] == ':'
 135     raise GetoptError('option -%s not recognized' % opt, opt)
 136
 137 if __name__ == '__main__':
 138     import sys
 139     print getopt(sys.argv[1:], "a:b", ["alpha=", "beta"])