//function extensions
Function.prototype.addMethod = function(name, func){
    if(!this.prototype[name]){
        this.prototype[name] = func;
    }
    return this;
};

//number extensions
Number.addMethod('toInteger', function(){
    return Math[this < 0 ? 'ceil' : 'floor'](this);
});

//string extensions
String.addMethod('trim', function(){
    return this.replace(/^\s+|\s+$/g, '');
});

String.addMethod('insertAt', function(loc, strChunk){
    var val = this.valueOf().substr(0, loc);
    return val + strChunk + this.valueOf().substr(loc);
});

//array extensions
Array.addMethod('toSet', function(){
    for(var i=0; i < this.length; i++){
         var val = this[i];
         for(var j=i+1; j < this.length; j++)
            if(this[j]==val)
                this.splice(j--, 1);
    }
    return this;
});

//first class functions
var range = function(start, end, step){
    if(step === undefined){
        var step = 1;
    }

    var nums = [];
    while(a != b){
        nums.push(a);
        a += step;
    }
    return nums;
};