Lib/distutils/fancy_getopt.py

   1 """distutils.fancy_getopt
   2
   3 Wrapper around the standard getopt module that provides the following
   4 additional features:
   5   * short and long options are tied together
   6   * options have help strings, so fancy_getopt could potentially
   7     create a complete usage summary
   8   * options set attributes of a passed-in object
   9 """
  10
  11 # created 1999/03/03, Greg Ward
  12
  13 __rcsid__ = "$Id$"
  14
  15 import string, re
  16 from types import *
  17 import getopt
  18 from distutils.errors import *
  19
  20 # Much like command_re in distutils.core, this is close to but not quite
  21 # the same as a Python NAME -- except, in the spirit of most GNU
  22 # utilities, we use '-' in place of '_'.  (The spirit of LISP lives on!)
  23 # The similarities to NAME are again not a coincidence...
  24 longopt_re = re.compile (r'^[a-zA-Z]([a-zA-Z0-9-]*)$')
  25
  26 # This is used to translate long options to legitimate Python identifiers
  27 # (for use as attributes of some object).
  28 longopt_xlate = string.maketrans ('-', '_')
  29
  30
  31 def fancy_getopt (options, object, args):
  32
  33     # The 'options' table is a list of 3-tuples:
  34     #   (long_option, short_option, help_string)
  35     # if an option takes an argument, its long_option should have '='
  36     # appended; short_option should just be a single character, no ':' in
  37     # any case.  If a long_option doesn't have a corresponding
  38     # short_option, short_option should be None.  All option tuples must
  39     # have long options.
  40
  41     # Build the short_opts string and long_opts list, remembering how
  42     # the two are tied together
  43
  44     short_opts = []                     # we'll join 'em when done
  45     long_opts = []
  46     short2long = {}
  47     attr_name = {}
  48     takes_arg = {}
  49
  50     for (long, short, help) in options:
  51         # Type-check the option names
  52         if type (long) is not StringType or len (long) < 2:
  53             raise DistutilsGetoptError, \
  54                   "long option must be a string of length >= 2"
  55
  56         if (not ((short is None) or
  57                  (type (short) is StringType and len (short) == 1))):
  58             raise DistutilsGetoptError, \
  59                   "short option must be None or string of length 1"
  60
  61         long_opts.append (long)
  62
  63         if long[-1] == '=':             # option takes an argument?
  64             if short: short = short + ':'
  65             long = long[0:-1]
  66             takes_arg[long] = 1
  67         else:
  68             takes_arg[long] = 0
  69
  70         # Now enforce some bondage on the long option name, so we can later
  71         # translate it to an attribute name in 'object'.  Have to do this a
  72         # bit late to make sure we've removed any trailing '='.
  73         if not longopt_re.match (long):
  74             raise DistutilsGetoptError, \
  75                   ("invalid long option name '%s' " +
  76                    "(must be letters, numbers, hyphens only") % long
  77
  78         attr_name[long] = string.translate (long, longopt_xlate)
  79         if short:
  80             short_opts.append (short)
  81             short2long[short[0]] = long
  82
  83     # end loop over 'options'
  84
  85     short_opts = string.join (short_opts)
  86     try:
  87         (opts, args) = getopt.getopt (args, short_opts, long_opts)
  88     except getopt.error, msg:
  89         raise DistutilsArgError, msg
  90
  91     for (opt, val) in opts:
  92         if len (opt) == 2 and opt[0] == '-': # it's a short option
  93             opt = short2long[opt[1]]
  94
  95         elif len (opt) > 2 and opt[0:2] == '--':
  96             opt = opt[2:]
  97
  98         else:
  99             raise RuntimeError, "getopt lies! (bad option string '%s')" % \
 100                   opt
 101
 102         attr = attr_name[opt]
 103         if takes_arg[opt]:
 104             setattr (object, attr, val)
 105         else:
 106             if val == '':
 107                 setattr (object, attr, 1)
 108             else:
 109                 raise RuntimeError, "getopt lies! (bad value '%s')" % value
 110
 111     # end loop over options found in 'args'
 112
 113     return args
 114
 115 # end fancy_getopt()