Patch 473512: add GNU style scanning as gnu_getopt.

Lib/getopt.py

@@ -5,20 +5,36 @@ 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:
+provides two functions and an exception:
 
 getopt() -- Parse command line options
+gnu_getopt() -- Like getopt(), but allow option and non-option arguments
+to be intermixed. 
 GetoptError -- exception (class) raised with 'opt' attribute, which is the
 option involved with the exception.
 """
 
 # Long option support added by Lars Wirzenius <liw@iki.fi>.
-
+#
 # Gerrit Holl <gerrit@nl.linux.org> moved the string-based exceptions
 # to class-based exceptions.
+#
+# Peter Åstrand <astrand@lysator.liu.se> added gnu_getopt().
+#
+# TODO for gnu_getopt():
+#
+# - GNU getopt_long_only mechanism
+# - allow the caller to specify ordering
+# - RETURN_IN_ORDER option
+# - GNU extension with '-' as first character of option string
+# - optional arguments, specified by double colons
+# - a option string with a W followed by semicolon should
+#   treat "-W foo" as "--foo"
 
 __all__ = ["GetoptError","error","getopt"]
 
+import os
+
 class GetoptError(Exception):
     opt = ''
     msg = ''
@@ -75,6 +91,56 @@ def getopt(args, shortopts, longopts = []):
 
     return opts, args
 
+def gnu_getopt(args, shortopts, longopts = []):
+    """getopt(args, options[, long_options]) -> opts, args
+
+    This function works like getopt(), except that GNU style scanning
+    mode is used by default. This means that option and non-option
+    arguments may be intermixed. The getopt() function stops
+    processing options as soon as a non-option argument is
+    encountered.
+
+    If the first character of the option string is `+', or if the
+    environment variable POSIXLY_CORRECT is set, then option
+    processing stops as soon as a non-option argument is encountered.
+    
+    """
+
+    opts = []
+    prog_args = []
+    if type(longopts) == type(""):
+        longopts = [longopts]
+    else:
+        longopts = list(longopts)
+
+    # Allow options after non-option arguments?
+    if shortopts.startswith('+'):
+        shortopts = shortopts[1:]
+        all_options_first = 1
+    elif os.getenv("POSIXLY_CORRECT"):
+        all_options_first = 1
+    else:
+        all_options_first = 0
+
+    while args:
+        if args[0] == '--':
+            prog_args += args[1:]
+            break
+
+        if args[0][:2] == '--':
+            opts, args = do_longs(opts, args[0][2:], longopts, args[1:])
+        elif args[0][:1] == '-':
+            opts, args = do_shorts(opts, args[0][1:], shortopts, args[1:])
+        else:
+            if all_options_first:
+                prog_args += args
+                break
+            else:
+                prog_args.append(args[0])
+                args = args[1:]
+
+    return opts, prog_args
+
 def do_longs(opts, opt, longopts, args):
     try:
         i = opt.index('=')