"""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 <[email protected]>.
#
# Gerrit Holl <[email protected]> moved the string-based exceptions
# to class-based exceptions.
#
# Peter Åstrand <[email protected]> added gnu_getopt().
#
# TODO for gnu_getopt():
#
# - GNU getopt_long_only mechanism
# - an option string with a W followed by semicolon should
# treat "-W foo" as "--foo"
__all__ = ["GetoptError","error","getopt","gnu_getopt"]
import os
from gettext import gettext as _
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 and options that accept an optional argument followed by
two colons (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
('='). Options which accept an optional argument should be
followed by an equal sign and question mark ('=?').
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 isinstance(longopts, str):
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)
return_in_order = False
if shortopts.startswith('-'):
shortopts = shortopts[1:]
all_options_first = False
return_in_order = True
# Allow options after non-option arguments?
elif 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] == '--':
if return_in_order and prog_args:
opts.append((None, prog_args))
prog_args = []
opts, args = do_longs(opts, args[0][2:], longopts, args[1:])
elif args[0][:1] == '-' and args[0] != '-':
if return_in_order and prog_args:
opts.append((None, prog_args))
prog_args = []
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 and has_arg != '?':
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
elif opt + '=?' in possibilities:
return '?', opt
# Possibilities must be unique to be accepted
if len(possibilities) > 1:
raise GetoptError(
_("option --%s not a unique prefix; possible options: %s")
% (opt, ", ".join(possibilities)),
opt,
)
assert len(possibilities) == 1
unique_match = possibilities[0]
if unique_match.endswith('=?'):
return '?', unique_match[:-2]
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:]
has_arg = short_has_arg(opt, shortopts)
if has_arg:
if optstring == '' and has_arg != '?':
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] != ':':
if not shortopts.startswith(':', i+1):
return False
if shortopts.startswith('::', i+1):
return '?'
return True
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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