summaryrefslogtreecommitdiffstats
path: root/Lib/getopt.py
blob: 251d89c5cfe9ad9c11768377c86140243d9f92ee (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
"""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 <liw@iki.fi>.
#
# Gerrit Holl <gerrit@nl.linux.org> moved the string-based exceptions
# to class-based exceptions.
#
# Peter Astrand <astrand@lysator.liu.se> added gnu_getopt().
#
# TODO for gnu_getopt():
#
# - GNU getopt_long_only mechanism
# - allow the caller to specify ordering
# - RETURN_IN_ORDER option
# - GNU extension with '-' as first character of option string
# - optional arguments, specified by double colons
# - a option string with a W followed by semicolon should
#   treat "-W foo" as "--foo"

__all__ = ["GetoptError","error","getopt","gnu_getopt"]

import os

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 (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)
    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)

    # Allow options after non-option arguments?
    if 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] == '--':
            opts, args = do_longs(opts, args[0][2:], longopts, args[1:])
        elif args[0][:1] == '-' and args[0] != '-':
            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:
            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
    # No exact match, so better be unique.
    if len(possibilities) > 1:
        # XXX since possibilities contains all valid continuations, might be
        # nice to work them into the error msg
        raise GetoptError('option --%s not a unique prefix' % opt, opt)
    assert len(possibilities) == 1
    unique_match = possibilities[0]
    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:]
        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.startswith(':', i+1)
    raise GetoptError('option -%s not recognized' % opt, opt)

if __name__ == '__main__':
    import sys
    print getopt(sys.argv[1:], "a:b", ["alpha=", "beta"])