compass-course-jslove.js

Array.range = function(start, end)
{
    if (!end)
    {
        end = start;
        start = 0;
    }

    var a = [];
    for (var i = start; i < end; i++)
        a.push(i);
    return a;
}

Array.prototype.each = function(callback)
{
    for (var i = 0; i < this.length; i++)
        callback(this[i], i);
}

Array.prototype.filter = function(condition)
{
    var a = [];
    this.each(function(v) { if (condition(v)) a.push(v); });
    return a;
}

Array.prototype.map = function(mapper)
{
    var a = [];
    this.each(function(v) { a.push(mapper(v)); });
    return a;
}

Math.even = function(v) { return v % 2 == 0; };
Math.odd = function(v) { return !Math.even(v); };
Math.mul = function(a, b) 
{ 
    return arguments.length >= 2 ? a * b : arguments.callee.curry(a);
};

Function.prototype.curry = function(first)
{
    var self = this;
    return function()
    {
        var args = [ first ];
        for (var i = 0; i < arguments.length; i++)
            args.push(arguments[i]);
        return self.apply(this, args);
    };
}

function alert(s) 
{ 
    WScript.Echo(s); 
}

function main()
{
    var i, args = [], range, filter, multiplier;
    for (i = 0; i < WScript.Arguments.length; i++)
        args.push(WScript.Arguments(i));

    if (args.length < 3)
    {
        throw new Error('Missing required arguments. Usage is: RANGE ( "odd" | "even" ) MULTIPLIER');
        WScript.Quit(1);
    }
    
    range = Number(args.shift());
    if (isNaN(range))
        throw new Error('Invalid range.');
    
    filter = Math[args.shift()];
    if (!filter)
        throw new Error("Invalid filter.");

    multiplier = Number(args.shift());
    if (isNaN(multiplier))
        throw new Error('Invalid multiplier.');
    
    Array.range(range)
         .filter(filter)
         .map(Math.mul(multiplier))
         .each(alert);
}

try
{
    main();
}
catch (e)
{
    alert(e.message);
    WScript.Quit(1);
}