JS: CLI argument parser.

options.js

/** Command-line options parser (http://valeriu.palos.ro/1026/).
    Copyright 2011 Valeriu Paloş (valeriu@palos.ro). All rights reserved.
    Released as Public Domain.

    Expects the "schema" array with options definitions and produces the
    "options" object and the "arguments" array, which will contain all
    non-option arguments encountered (including the script name and such).

    Syntax:
        [«short», «long», «attributes», «brief», «callback»]

    Attributes:
        ! - option is mandatory;
        : - option expects a parameter;
        + - option may be specified multiple times (repeatable).

    Notes:
        - Parser is case-sensitive.
        - The '-h|--help' option is provided implicitly.
        - Parsed options are placed as fields in the "options" object.
        - Non-option arguments are placed in the "arguments" array.
        - Options and their parameters must be separated by space.
        - Either one of «short» or «long» must always be provided.
        - The «callback» function is optional.
        - Cumulated short options are supported (i.e. '-tv').
        - If an error occurs, the process is halted and the help is shown.
        - Repeatable options will be cumulated into arrays.
        - The parser does *not* test for duplicate option definitions.
    */

// Sample option definitions.
var schema = [
    ['f', 'file',    '!:', "Some file we really need.",
                           function(data) {
                               console.log("Hello: " + data);
                           } ],
    ['t', 'test',    '!',  'I am needed also.'],
    ['d', '',        '',   'Enable debug mode.'],
    ['',  'level',   ':',  'Debug level (values 0-4).'],
    ['v', 'verbose', '+',  'Verbosity levels (can be used repeatedly).'],
];

// Parse options.
try {
    var tokens = [];
    var options = {};
    var arguments = [];
    for (var i = 0, item = process.argv[0]; i < process.argv.length; i++, item = process.argv[i]) {
        if (item.charAt(0) == '-') {
            if (item.charAt(1) == '-') {
                tokens.push('--', item.slice(2));
            } else {
                tokens = tokens.concat(item.split('').join('-').split('').slice(1));
            }
        } else {
            tokens.push(item);
        }
    }
    while (type = tokens.shift()) {
        if (type == '-' || type == '--') {
            var name = tokens.shift();
            if (name == 'help' || name == 'h') {
                throw 'help';
                continue;
            }
            var option = null;
            for (var i = 0, item = schema[0]; i < schema.length; i++, item = schema[i]) {
                if (item[type.length - 1] == name) {
                    option = item;
                    break;
                }
            }
            if (!option) {
                throw "Unknown option '" + type + name + "' encountered!";
            }
            var value = true;
            if ((option[2].indexOf(':') != -1) && !(value = tokens.shift())) {
                throw "Option '" + type + name + "' expects a parameter!";
            }
            var index = option[1] || option[0];
            if (option[2].indexOf('+') != -1) {
                options[index] = options[index] instanceof Array ? options[index] : [];
                options[index].push(value);
            } else {
                options[index] = value;
            }
            if (typeof(option[4]) == 'function') {
                option[4](value);
            }
            option[2] = option[2].replace('!', '');
        } else {
            arguments.push(type);
            continue;
        }
    }
    for (var i = 0, item = schema[0]; i < schema.length; i++, item = schema[i]) {
        if (item[2].indexOf('!') != -1) {
            throw "Option '" + (item[1] ? '--' + item[1] : '-' + item[0]) +
                  "' is mandatory and was not given!";
        }
    }
} catch(e) {
    if (e == 'help') {
        console.log("Usage: ./«script» «options» «values»\n");
        console.log("Options:");
        for (var i = 0, item = schema[0]; i < schema.length; i++, item = schema[i]) {
            var names = (item[0] ? '-' + item[0] + (item[1] ? '|' : ''): '   ') +
                        (item[1] ? '--' + item[1] : '');
            var syntax = names + (item[2].indexOf(':') != -1 ? ' «value»' : '');
            syntax += syntax.length < 20 ? new Array(20 - syntax.length).join(' ') : '';
            console.log("\t" + (item[2].indexOf('!') != -1 ? '*' : ' ')
                             + (item[2].indexOf('+') != -1 ? '+' : ' ')
                             + syntax + "\t" + item[3]);
        }
        console.log("\n\t  (* mandatory option)\n\t  (+ repeatable option)\n");
        process.exit(0);
    }
    console.error(e);
    console.error("Use  the '-h|--help' option for usage details.");
    process.exit(1);
}

// Continue with your script...