342 lines
13 KiB
Python
342 lines
13 KiB
Python
# Copyright (C) 2009-2010 Alexander Cherniuk <ts33kr@gmail.com>
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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"""
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The module contains routines to parse command arguments and map them to
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the command handler's positonal and keyword arguments.
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Mapping is done in two stages: 1) parse arguments into positional
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arguments and options; 2) adapt them to the specific command handler
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according to the command properties.
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"""
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import re
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from operator import itemgetter
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from .errors import DefinitionError, CommandError
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# Quite complex piece of regular expression logic to parse options and
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# arguments. Might need some tweaking along the way.
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ARG_PATTERN = re.compile(r'(\'|")?(?P<body>(?(1).+?|\S+))(?(1)\1)')
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OPT_PATTERN = re.compile(r'(?<!\w)--?(?P<key>[\w-]+)(?:(?:=|\s)(\'|")?(?P<value>(?(2)[^-]+?|[^-\s]+))(?(2)\2))?')
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# Option keys needs to be encoded to a specific encoding as Python does
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# not allow to expand dictionary with raw unicode strings as keys from a
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# **kwargs.
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KEY_ENCODING = 'UTF-8'
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# Defines how complete representation of command usage (generated based
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# on command handler argument specification) will be rendered.
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USAGE_PATTERN = 'Usage: %s %s'
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def parse_arguments(arguments):
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"""
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Simple yet effective and sufficient in most cases parser which
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parses command arguments and returns them as two lists.
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First list represents positional arguments as (argument, position),
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and second representing options as (key, value, position) tuples,
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where position is a (start, end) span tuple of where it was found in
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the string.
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Options may be given in --long or -short format. As --option=value
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or --option value or -option value. Keys without values will get
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None as value.
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Arguments and option values that contain spaces may be given as 'one
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two three' or "one two three"; that is between single or double
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quotes.
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"""
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args, opts = [], []
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def intersects_opts(given_start, given_end):
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"""
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Check if given span intersects with any of options.
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"""
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for key, value, (start, end) in opts:
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if given_start >= start and given_end <= end:
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return True
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return False
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def intersects_args(given_start, given_end):
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"""
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Check if given span intersects with any of arguments.
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"""
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for arg, (start, end) in args:
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if given_start >= start and given_end <= end:
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return True
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return False
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for match in re.finditer(OPT_PATTERN, arguments):
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if match:
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key = match.group('key')
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value = match.group('value') or None
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position = match.span()
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opts.append((key, value, position))
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for match in re.finditer(ARG_PATTERN, arguments):
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if match:
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body = match.group('body')
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position = match.span()
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args.append((body, position))
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# Primitive but sufficiently effective way of disposing of
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# conflicted sectors. Remove any arguments that intersect with
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# options.
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for arg, position in args[:]:
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if intersects_opts(*position):
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args.remove((arg, position))
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# Primitive but sufficiently effective way of disposing of
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# conflicted sectors. Remove any options that intersect with
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# arguments.
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for key, value, position in opts[:]:
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if intersects_args(*position):
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opts.remove((key, value, position))
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return args, opts
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def adapt_arguments(command, arguments, args, opts):
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"""
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Adapt args and opts got from the parser to a specific handler by
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means of arguments specified on command definition. That is
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transform them to *args and **kwargs suitable for passing to a
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command handler.
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Dashes (-) in the option names will be converted to underscores. So
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you can map --one-more-option to a one_more_option=None.
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If the initial value of a keyword argument is a boolean (False in
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most cases) - then this option will be treated as a switch, that is
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an option which does not take an argument. If a switch is followed
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by an argument - then this argument will be treated just like a
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normal positional argument.
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"""
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spec_args, spec_kwargs, var_args, var_kwargs = command.extract_specification()
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norm_kwargs = dict(spec_kwargs)
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# Quite complex piece of neck-breaking logic to extract raw
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# arguments if there is more, then one positional argument specified
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# by the command. In case if it's just one argument which is the
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# collector - this is fairly easy. But when it's more then one
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# argument - the neck-breaking logic of how to retrieve residual
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# arguments as a raw, all in one piece string, kicks in.
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if command.raw:
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if arguments:
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spec_fix = 1 if command.source else 0
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spec_len = len(spec_args) - spec_fix
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arguments_end = len(arguments) - 1
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# If there are any optional arguments given they should be
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# either an unquoted postional argument or part of the raw
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# argument. So we find all optional arguments that can
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# possibly be unquoted argument and append them as is to the
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# args.
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for key, value, (start, end) in opts[:spec_len]:
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if value:
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end -= len(value) + 1
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args.append((arguments[start:end], (start, end)))
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args.append((value, (end, end + len(value) + 1)))
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else:
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args.append((arguments[start:end], (start, end)))
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# We need in-place sort here because after manipulations
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# with options order of arguments might be wrong and we just
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# can't have more complex logic to not let that happen.
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args.sort(key=itemgetter(1))
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if spec_len > 1:
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try:
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stopper, (start, end) = args[spec_len - 2]
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except IndexError:
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raise CommandError(_("Missing arguments"), command)
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# The essential point of the whole play. After
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# boundaries are being determined (supposingly correct)
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# we separate raw part from the rest of arguments, which
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# should be normally processed.
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raw = arguments[end:]
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raw = raw.strip() or None
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if not raw and not command.empty:
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raise CommandError(_("Missing arguments"), command)
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# Discard residual arguments and all of the options as
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# raw command does not support options and if an option
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# is given it is rather a part of a raw argument.
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args = args[:spec_len - 1]
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opts = []
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args.append((raw, (end, arguments_end)))
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else:
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# Substitue all of the arguments with only one, which
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# contain raw and unprocessed arguments as a string. And
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# discard all the options, as raw command does not
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# support them.
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args = [(arguments, (0, arguments_end))]
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opts = []
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else:
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if command.empty:
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args.append((None, (0, 0)))
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else:
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raise CommandError(_("Missing arguments"), command)
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# The first stage of transforming options we have got to a format
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# that can be used to associate them with declared keyword
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# arguments. Substituting dashes (-) in their names with
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# underscores (_).
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for index, (key, value, position) in enumerate(opts):
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if '-' in key:
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opts[index] = (key.replace('-', '_'), value, position)
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# The second stage of transforming options to an associatable state.
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# Expanding short, one-letter options to a verbose ones, if
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# corresponding optin has been given.
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if command.expand:
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expanded = []
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for spec_key, spec_value in norm_kwargs.items():
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letter = spec_key[0] if len(spec_key) > 1 else None
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if letter and letter not in expanded:
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for index, (key, value, position) in enumerate(opts):
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if key == letter:
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expanded.append(letter)
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opts[index] = (spec_key, value, position)
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break
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# Detect switches and set their values accordingly. If any of them
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# carries a value - append it to args.
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for index, (key, value, position) in enumerate(opts):
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if isinstance(norm_kwargs.get(key), bool):
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opts[index] = (key, True, position)
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if value:
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args.append((value, position))
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# Sorting arguments and options (just to be sure) in regarding to
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# their positions in the string.
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args.sort(key=itemgetter(1))
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opts.sort(key=itemgetter(2))
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# Stripping down position information supplied with arguments and
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# options as it won't be needed again.
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args = list(map(lambda t: t[0], args))
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opts = list(map(lambda t: (t[0], t[1]), opts))
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# If command has extra option enabled - collect all extra arguments
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# and pass them to a last positional argument command defines as a
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# list.
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if command.extra:
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if not var_args:
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spec_fix = 1 if not command.source else 2
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spec_len = len(spec_args) - spec_fix
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extra = args[spec_len:]
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args = args[:spec_len]
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args.append(extra)
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else:
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raise DefinitionError("Can not have both, extra and *args")
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# Detect if positional arguments overlap keyword arguments. If so
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# and this is allowed by command options - then map them directly to
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# their options, so they can get propert further processings.
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spec_fix = 1 if command.source else 0
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spec_len = len(spec_args) - spec_fix
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if len(args) > spec_len:
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if command.overlap:
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overlapped = args[spec_len:]
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args = args[:spec_len]
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for arg, (spec_key, spec_value) in zip(overlapped, spec_kwargs):
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opts.append((spec_key, arg))
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else:
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raise CommandError(_("Too many arguments"), command)
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# Detect every switch and ensure it will not receive any arguments.
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# Normally this does not happen unless overlapping is enabled.
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for key, value in opts:
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initial = norm_kwargs.get(key)
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if isinstance(initial, bool):
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if not isinstance(value, bool):
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raise CommandError("%s: Switch can not take an argument" % key, command)
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# Inject the source arguments as a string as a first argument, if
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# command has enabled the corresponding option.
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if command.source:
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args.insert(0, arguments)
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# Return *args and **kwargs in the form suitable for passing to a
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# command handler and being expanded.
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return tuple(args), dict(opts)
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def generate_usage(command, complete=True):
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"""
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Extract handler's arguments specification and wrap them in a
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human-readable format usage information. If complete is given - then
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USAGE_PATTERN will be used to render the specification completly.
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"""
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spec_args, spec_kwargs, var_args, var_kwargs = command.extract_specification()
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# Remove some special positional arguments from the specifiaction,
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# but store their names so they can be used for usage info
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# generation.
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sp_source = spec_args.pop(0) if command.source else None
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sp_extra = spec_args.pop() if command.extra else None
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kwargs = []
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letters = []
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for key, value in spec_kwargs:
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letter = key[0]
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key = key.replace('_', '-')
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if isinstance(value, bool):
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value = str()
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else:
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value = '=%s' % value
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if letter not in letters:
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kwargs.append('-(-%s)%s%s' % (letter, key[1:], value))
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letters.append(letter)
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else:
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kwargs.append('--%s%s' % (key, value))
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usage = str()
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args = str()
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if command.raw:
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spec_len = len(spec_args) - 1
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if spec_len:
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args += ('<%s>' % ', '.join(spec_args[:spec_len])) + ' '
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args += ('(|%s|)' if command.empty else '|%s|') % spec_args[-1]
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else:
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if spec_args:
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args += '<%s>' % ', '.join(spec_args)
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if var_args or sp_extra:
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args += (' ' if spec_args else str()) + '<<%s>>' % (var_args or sp_extra)
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usage += args
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if kwargs or var_kwargs:
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if kwargs:
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usage += (' ' if args else str()) + '[%s]' % ', '.join(kwargs)
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if var_kwargs:
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usage += (' ' if args else str()) + '[[%s]]' % var_kwargs
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# Native name will be the first one if it is included. Otherwise,
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# names will be in the order they were specified.
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if len(command.names) > 1:
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names = '%s (%s)' % (command.first_name, ', '.join(command.names[1:]))
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else:
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names = command.first_name
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return USAGE_PATTERN % (names, usage) if complete else usage
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