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144 lines
5.1 KiB
144 lines
5.1 KiB
"""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 a single function and an exception: |
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getopt() -- Parse command line options |
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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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# Gerrit Holl <gerrit@nl.linux.org> moved the string-based exceptions |
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# to class-based exceptions. |
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__all__ = ["GetoptError","error","getopt"] |
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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 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: |
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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 0, opt |
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elif opt + '=' in possibilities: |
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return 1, 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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