Accept a non-list sequence for the long options (request by Jack Jansen).

Because it might be a common mistake to pass a single string, this
situation is treated separately.

Since we were making a copy of the longopts list anyway, we now use
the list() function -- this made it necessary to change all uses of
the local variable (and argument) 'list' to something more meaningful,
i.e., 'opts'.

Also added docstrings (copied from the library manual) and removed the
(now redundant) module comments.

Author: gvanrossum

Lib/getopt.py

@@ -1,52 +1,67 @@
-# module getopt -- Standard command line processing.
-
-# Function getopt.getopt() has a different interface but provides the
-# similar functionality to the Unix getopt() function, with the
-# addition of long-option support.  (Long option support added by Lars
-# Wirzenius <liw@iki.fi>.)
-
-# It has two required arguments: the first should be argv[1:] (it
-# doesn't want the script name), the second the string of option
-# letters as passed to Unix getopt() (i.e., a string of allowable
-# option letters, with options requiring an argument followed by a
-# colon).
-
-# The optional third argument, if present, getopt.getopt works similar
-# to the GNU getopt_long function (but optional arguments are not
-# supported).  The third argument should be a list of strings that
-# name the long options.  If the name ends '=', the argument requires
-# an argument.
-
-# It raises the exception getopt.error with a string argument if it
-# detects an error.
-
-# It returns two values:
-# (1)   a list of pairs (option, option_argument) giving the options in
-#       the order in which they were specified.  (I'd use a dictionary
-#       but applications may depend on option order or multiple
-#       occurrences.)  Boolean options have '' as option_argument.
-# (2)   the list of remaining arguments (may be empty).
+"""Module getopt -- Parser for command line options.
+
+This module helps scripts to parse the command line arguments in
+sys.argv.  It supports the same conventions as the Unix getopt()
+function (including the special meanings of arguments of the form `-'
+and `--').  Long options similar to those supported by GNU software
+may be used as well via an optional third argument.  This module
+provides a single function and an exception:
+
+getopt() -- Parse command line options
+error    -- Exception (string) raised when bad options are found
+"""
+
+# Long option support added by Lars Wirzenius <liw@iki.fi>.
 
 import string
 
 error = 'getopt.error'
 
 def getopt(args, shortopts, longopts = []):
-    list = []
-    longopts = longopts[:]
+    """getopt(args, options[, long_options]) -> opts, args
+
+    Parses command line options and parameter list.  args is the
+    argument list to be parsed, without the leading reference to the
+    running program.  Typically, this means "sys.argv[1:]".  shortopts
+    is the string of option letters that the script wants to
+    recognize, with options that require an argument followed by a
+    colon (i.e., the same format that Unix getopt() uses).  If
+    specified, longopts is a list of strings with the names of the
+    long options which should be supported.  The leading '--'
+    characters should not be included in the option name.  Options
+    which require an argument should be followed by an equal sign
+    ('=').
+
+    The return value consists of two elements: the first is a list of
+    (option, value) pairs; the second is the list of program arguments
+    left after the option list was stripped (this is a trailing slice
+    of the first argument).  Each option-and-value pair returned has
+    the option as its first element, prefixed with a hyphen (e.g.,
+    '-x'), and the option argument as its second element, or an empty
+    string if the option has no argument.  The options occur in the
+    list in the same order in which they were found, thus allowing
+    multiple occurrences.  Long and short options may be mixed.
+
+    """
+
+    opts = []
+    if type(longopts) == type(""):
+        longopts = [longopts]
+    else:
+        longopts = list(longopts)
     longopts.sort()
     while args and args[0][:1] == '-' and args[0] != '-':
         if args[0] == '--':
             args = args[1:]
             break
         if args[0][:2] == '--':
-            list, args = do_longs(list, args[0][2:], longopts, args[1:])
+            opts, args = do_longs(opts, args[0][2:], longopts, args[1:])
         else:
-            list, args = do_shorts(list, args[0][1:], shortopts, args[1:])
+            opts, args = do_shorts(opts, args[0][1:], shortopts, args[1:])
 
-    return list, args
+    return opts, args
 
-def do_longs(list, opt, longopts, args):
+def do_longs(opts, opt, longopts, args):
     try:
         i = string.index(opt, '=')
         opt, optarg = opt[:i], opt[i+1:]
@@ -61,8 +76,8 @@ def do_longs(list, opt, longopts, args):
             optarg, args = args[0], args[1:]
     elif optarg:
         raise error, 'option --%s must not have an argument' % opt
-    list.append(('--' + opt, optarg or ''))
-    return list, args
+    opts.append(('--' + opt, optarg or ''))
+    return opts, args
 
 # Return:
 #   has_arg?
@@ -81,7 +96,7 @@ def long_has_args(opt, longopts):
         return 0, longopts[i]
     raise error, 'option --' + opt + ' not recognized'
 
-def do_shorts(list, optstring, shortopts, args):
+def do_shorts(opts, optstring, shortopts, args):
     while optstring != '':
         opt, optstring = optstring[0], optstring[1:]
         if short_has_arg(opt, shortopts):
@@ -92,8 +107,8 @@ def do_shorts(list, optstring, shortopts, args):
             optarg, optstring = optstring, ''
         else:
             optarg = ''
-        list.append(('-' + opt, optarg))
-    return list, args
+        opts.append(('-' + opt, optarg))
+    return opts, args
 
 def short_has_arg(opt, shortopts):
     for i in range(len(shortopts)):