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- """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 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
- # - an option string with a W followed by semicolon should
- # treat "-W foo" as "--foo"
- __all__ = ["GetoptError","error","getopt","gnu_getopt"]
- import os
- try:
- from gettext import gettext as _
- except ImportError:
- # Bootstrapping Python: gettext's dependencies not built yet
- def _(s): return s
- class GetoptError(Exception):
- opt = ''
- msg = ''
- def __init__(self, msg, opt=''):
- self.msg = msg
- self.opt = opt
- Exception.__init__(self, msg, opt)
- def __str__(self):
- return self.msg
- error = GetoptError # backward compatibility
- def getopt(args, shortopts, 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)
- while args and args[0].startswith('-') and args[0] != '-':
- if args[0] == '--':
- args = args[1:]
- break
- if args[0].startswith('--'):
- opts, args = do_longs(opts, args[0][2:], longopts, args[1:])
- else:
- opts, args = do_shorts(opts, args[0][1:], shortopts, args[1:])
- 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 isinstance(longopts, str):
- longopts = [longopts]
- else:
- longopts = list(longopts)
- # Allow options after non-option arguments?
- if shortopts.startswith('+'):
- shortopts = shortopts[1:]
- all_options_first = True
- elif os.environ.get("POSIXLY_CORRECT"):
- all_options_first = True
- else:
- all_options_first = False
- 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] == '-' and args[0] != '-':
- 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('=')
- except ValueError:
- optarg = None
- else:
- opt, optarg = opt[:i], opt[i+1:]
- has_arg, opt = long_has_args(opt, longopts)
- if has_arg:
- if optarg is None:
- if not args:
- raise GetoptError(_('option --%s requires argument') % opt, opt)
- optarg, args = args[0], args[1:]
- elif optarg is not None:
- raise GetoptError(_('option --%s must not have an argument') % opt, opt)
- opts.append(('--' + opt, optarg or ''))
- return opts, args
- # Return:
- # has_arg?
- # full option name
- def long_has_args(opt, longopts):
- possibilities = [o for o in longopts if o.startswith(opt)]
- if not possibilities:
- raise GetoptError(_('option --%s not recognized') % opt, opt)
- # Is there an exact match?
- if opt in possibilities:
- return False, opt
- elif opt + '=' in possibilities:
- return True, opt
- # No exact match, so better be unique.
- if len(possibilities) > 1:
- # XXX since possibilities contains all valid continuations, might be
- # nice to work them into the error msg
- raise GetoptError(_('option --%s not a unique prefix') % opt, opt)
- assert len(possibilities) == 1
- unique_match = possibilities[0]
- has_arg = unique_match.endswith('=')
- if has_arg:
- unique_match = unique_match[:-1]
- return has_arg, unique_match
- def do_shorts(opts, optstring, shortopts, args):
- while optstring != '':
- opt, optstring = optstring[0], optstring[1:]
- if short_has_arg(opt, shortopts):
- if optstring == '':
- if not args:
- raise GetoptError(_('option -%s requires argument') % opt,
- opt)
- optstring, args = args[0], args[1:]
- optarg, optstring = optstring, ''
- else:
- optarg = ''
- opts.append(('-' + opt, optarg))
- return opts, args
- def short_has_arg(opt, shortopts):
- for i in range(len(shortopts)):
- if opt == shortopts[i] != ':':
- return shortopts.startswith(':', i+1)
- raise GetoptError(_('option -%s not recognized') % opt, opt)
- if __name__ == '__main__':
- import sys
- print(getopt(sys.argv[1:], "a:b", ["alpha=", "beta"]))
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