cpython/Lib/getopt.py
Guido van Rossum 80c33e562d Contribution from Gerrit Holl:
This patch changes the string-based exceptions to class-based
exceptions, so that you can fetch the unknown option as an
attribute.  As far as I know, it is backward compatible.

[The new exception class is called GetoptError; the name error is an
alias for compatibility.]
1999-12-21 22:38:40 +00:00

140 lines
4.9 KiB
Python

"""Module getopt -- 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 a single function and an exception:
Gerrit Holl <gerrit@nl.linux.org> moved the string-based exceptions
to class-based exceptions.
getopt() -- Parse command line options
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>.
import string
class GetoptError(Exception):
opt = ''
msg = ''
def __init__(self, *args):
self.args = args
if len(args) == 1:
self.msg = args[0]
elif len(args) == 2:
self.msg = args[0]
self.opt = args[1]
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)
longopts.sort()
while args and args[0][:1] == '-' and args[0] != '-':
if args[0] == '--':
args = args[1:]
break
if args[0][:2] == '--':
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 do_longs(opts, opt, longopts, args):
try:
i = string.index(opt, '=')
opt, optarg = opt[:i], opt[i+1:]
except ValueError:
optarg = None
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:
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):
optlen = len(opt)
for i in range(len(longopts)):
x, y = longopts[i][:optlen], longopts[i][optlen:]
if opt != x:
continue
if y != '' and y != '=' and i+1 < len(longopts):
if opt == longopts[i+1][:optlen]:
raise GetoptError('option --%s not a unique prefix' % opt, opt)
if longopts[i][-1:] in ('=', ):
return 1, longopts[i][:-1]
return 0, longopts[i]
raise GetoptError('option --%s not recognized' % opt, opt)
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[i+1:i+2] == ':'
raise GetoptError('option -%s not recognized' % opt, opt)
if __name__ == '__main__':
import sys
print getopt(sys.argv[1:], "a:b", ["alpha=", "beta"])