getopt-py

A classic getopt library for Python with long options and optional arguments support.

Motivation

For developers that find argparse too constraining.

Example

import getopts

...

getopt = getopts.getopts(sys.argv, {
    "h": 0         , "help"   : 0,
    "o": 1         , "output" : 1,
    "p": is_port   , "port"   : is_port,
    "v": [is_int,1], "verbose": [is_int,1]
})

for c in getopt:
    if   c in ("-")           : opts.files.append(getopt.optarg)
    elif c in ("h", "help")   : usage() ; sys.exit(0)
    elif c in ("o", "output") : opts.output  = getopt.optarg
    elif c in ("p", "port")   : opts.port    = int(getopt.optarg)
    elif c in ("v", "verbose"): opts.verbose = int(getopt.optarg)
    else: sys.exit(1)

• -h and --help take no arguments (0).
• -o and --output take any argument (1).
• -p and --port take an argument that, when passed to the is_port function, returns True.
• -v and --verbose take an optional argument that, when passed to the is_int function, returns True. If no argument is specified, it defaults to 1.

See example.py for a more complete example.

Features

The features are based on GNU getopt_long:

• Short options. Options may be combined (-a -b -c is equivalent to -abc). If the option takes a mandatory argument, the argument may appear with or without whitespaces (-o value is equivalent to -ovalue).

• Long options. If the option takes a mandatory argument, the argument may appear with or without an equal sign (--option value is equivalent to --option=value).

• Optional arguments. If the option takes an optional argument, the argument must appear without a space after a short option (-ovalue) or with an equal sign after a long option (--option=value).

• Options may appear in any order.

• -- can be used to denote the end of options.

Installation

With pip:

pip install getopts

(note the plural 's')

With [dpm]:

dpm install https://github.com/markuskimius/getopt-py.git

Usage

getopts.getopts(argv, optdict)

All parameters are mandatory:

• argv - The argument list (e.g., sys.argv)
• optdict - A dictionary containing the valid options and a specification of whether they take an argument. The keys are the options. The value may be 0 if the option takes no argument, or 1 if it takes an argument. Instead of 0 or 1, it may specify a validation function that returns 1 if the argument is valid, or 0 otherwise. To specify the argument as optional, surround it in brackets (make it a list), with the optional second element specifying the default value.

The function returns an iterable object that, if evaluated, returns one of the following:

• -: An optionless argument. The value of the argument is stored in getopt.optarg.
• ?: An invalid option. An error message has been printed to getopt.stderr and the option that caused the error is stored in getopt.optopt.
• All other values: A valid option. This value is also stored in getopt.optopt. If the option takes an argument, the value is stored in getopt.optarg.

The following variable names are available:

• getopt.optind: The index of the next argv.
• getopt.optopt: The last option processed.
• getopt.optarg: The argument to the last option.

License

Apache 2.0

[dpm]: https://github.com/markuskimius/dpm