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212 lines
7.2 KiB
Python
212 lines
7.2 KiB
Python
# -*- coding: utf-8 -*-
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"""Parser for command line options.
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This module helps scripts to parse the command line arguments in
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sys.argv. It supports the same conventions as the Unix getopt()
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function (including the special meanings of arguments of the form `-'
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and `--'). Long options similar to those supported by GNU software
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may be used as well via an optional third argument. This module
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provides two functions and an exception:
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getopt() -- Parse command line options
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gnu_getopt() -- Like getopt(), but allow option and non-option arguments
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to be intermixed.
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GetoptError -- exception (class) raised with 'opt' attribute, which is the
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option involved with the exception.
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"""
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# Long option support added by Lars Wirzenius <liw@iki.fi>.
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#
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# Gerrit Holl <gerrit@nl.linux.org> moved the string-based exceptions
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# to class-based exceptions.
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#
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# Peter Ã
strand <astrand@lysator.liu.se> added gnu_getopt().
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#
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# TODO for gnu_getopt():
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#
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# - GNU getopt_long_only mechanism
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# - allow the caller to specify ordering
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# - RETURN_IN_ORDER option
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# - GNU extension with '-' as first character of option string
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# - optional arguments, specified by double colons
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# - a option string with a W followed by semicolon should
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# treat "-W foo" as "--foo"
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__all__ = ["GetoptError","error","getopt","gnu_getopt"]
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import os
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class GetoptError(Exception):
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opt = ''
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msg = ''
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def __init__(self, msg, opt=''):
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self.msg = msg
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self.opt = opt
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Exception.__init__(self, msg, opt)
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def __str__(self):
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return self.msg
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error = GetoptError # backward compatibility
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def getopt(args, shortopts, longopts = []):
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"""getopt(args, options[, long_options]) -> opts, args
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Parses command line options and parameter list. args is the
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argument list to be parsed, without the leading reference to the
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running program. Typically, this means "sys.argv[1:]". shortopts
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is the string of option letters that the script wants to
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recognize, with options that require an argument followed by a
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colon (i.e., the same format that Unix getopt() uses). If
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specified, longopts is a list of strings with the names of the
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long options which should be supported. The leading '--'
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characters should not be included in the option name. Options
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which require an argument should be followed by an equal sign
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('=').
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The return value consists of two elements: the first is a list of
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(option, value) pairs; the second is the list of program arguments
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left after the option list was stripped (this is a trailing slice
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of the first argument). Each option-and-value pair returned has
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the option as its first element, prefixed with a hyphen (e.g.,
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'-x'), and the option argument as its second element, or an empty
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string if the option has no argument. The options occur in the
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list in the same order in which they were found, thus allowing
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multiple occurrences. Long and short options may be mixed.
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"""
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opts = []
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if type(longopts) == type(""):
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longopts = [longopts]
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else:
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longopts = list(longopts)
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while args and args[0].startswith('-') and args[0] != '-':
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if args[0] == '--':
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args = args[1:]
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break
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if args[0].startswith('--'):
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opts, args = do_longs(opts, args[0][2:], longopts, args[1:])
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else:
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opts, args = do_shorts(opts, args[0][1:], shortopts, args[1:])
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return opts, args
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def gnu_getopt(args, shortopts, longopts = []):
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"""getopt(args, options[, long_options]) -> opts, args
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This function works like getopt(), except that GNU style scanning
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mode is used by default. This means that option and non-option
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arguments may be intermixed. The getopt() function stops
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processing options as soon as a non-option argument is
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encountered.
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If the first character of the option string is `+', or if the
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environment variable POSIXLY_CORRECT is set, then option
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processing stops as soon as a non-option argument is encountered.
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"""
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opts = []
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prog_args = []
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if isinstance(longopts, str):
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longopts = [longopts]
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else:
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longopts = list(longopts)
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# Allow options after non-option arguments?
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if shortopts.startswith('+'):
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shortopts = shortopts[1:]
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all_options_first = True
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elif os.environ.get("POSIXLY_CORRECT"):
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all_options_first = True
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else:
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all_options_first = False
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while args:
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if args[0] == '--':
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prog_args += args[1:]
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break
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if args[0][:2] == '--':
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opts, args = do_longs(opts, args[0][2:], longopts, args[1:])
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elif args[0][:1] == '-' and args[0] != '-':
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opts, args = do_shorts(opts, args[0][1:], shortopts, args[1:])
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else:
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if all_options_first:
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prog_args += args
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break
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else:
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prog_args.append(args[0])
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args = args[1:]
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return opts, prog_args
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def do_longs(opts, opt, longopts, args):
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try:
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i = opt.index('=')
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except ValueError:
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optarg = None
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else:
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opt, optarg = opt[:i], opt[i+1:]
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has_arg, opt = long_has_args(opt, longopts)
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if has_arg:
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if optarg is None:
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if not args:
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raise GetoptError('option --%s requires argument' % opt, opt)
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optarg, args = args[0], args[1:]
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elif optarg is not None:
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raise GetoptError('option --%s must not have an argument' % opt, opt)
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opts.append(('--' + opt, optarg or ''))
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return opts, args
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# Return:
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# has_arg?
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# full option name
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def long_has_args(opt, longopts):
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possibilities = [o for o in longopts if o.startswith(opt)]
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if not possibilities:
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raise GetoptError('option --%s not recognized' % opt, opt)
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# Is there an exact match?
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if opt in possibilities:
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return False, opt
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elif opt + '=' in possibilities:
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return True, opt
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# No exact match, so better be unique.
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if len(possibilities) > 1:
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# XXX since possibilities contains all valid continuations, might be
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# nice to work them into the error msg
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raise GetoptError('option --%s not a unique prefix' % opt, opt)
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assert len(possibilities) == 1
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unique_match = possibilities[0]
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has_arg = unique_match.endswith('=')
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if has_arg:
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unique_match = unique_match[:-1]
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return has_arg, unique_match
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def do_shorts(opts, optstring, shortopts, args):
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while optstring != '':
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opt, optstring = optstring[0], optstring[1:]
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if short_has_arg(opt, shortopts):
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if optstring == '':
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if not args:
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raise GetoptError('option -%s requires argument' % opt,
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opt)
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optstring, args = args[0], args[1:]
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optarg, optstring = optstring, ''
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else:
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optarg = ''
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opts.append(('-' + opt, optarg))
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return opts, args
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def short_has_arg(opt, shortopts):
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for i in range(len(shortopts)):
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if opt == shortopts[i] != ':':
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return shortopts.startswith(':', i+1)
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raise GetoptError('option -%s not recognized' % opt, opt)
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if __name__ == '__main__':
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import sys
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print(getopt(sys.argv[1:], "a:b", ["alpha=", "beta"]))
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