Call and Apply replica in Pure JS

call_and_apply.js

function x(a,b,c) {
    console.log('Called X:', a,b,c);
}

Function.prototype._call = function() {
    var first = Array.prototype.shift.apply(arguments);
    this.apply(first, arguments);
};

Function.prototype._apply = function() {
    var first = Array.prototype.shift.call(arguments);
    var str = [];
    for (var i = 0; i < arguments[0].length; i++) str.push('arguments[0]['+i+']');
    eval('this.call(first,' + str.join(',') + ')');
};

x._apply(null, [1,2,3]);
x._call(null, 1,2,3);