Array.prototype.map = function (f) {
	var n = [];
	for (var i = 0; i < this.length; i++) {
		n[i] = f(this[i])
	}
	return n
}

trace([1, 3, 7].map(Math.sin));

function isEven(x) {return 1 - (x % 2)};
function isOdd(x) {return not isEven(x)};

trace([1, 2, 3, 7, 10].map(isEven));
trace([1, 2, 3, 7, 10].map(isOdd));

Array.prototype.over = function (f) {
	var r;
	for (var i = 0; i < this.length; i++) {
		r = f(r, this[i])
	}
	return r
}

trace([1, 2, 3].over(function (total, x) {return total + x}));

function sum(a, b) {return a + b};
trace([1, 2, 3].over(sum));

Array.prototype.sum = function() {return this.over(sum)}

// k: +/1 2 3
trace([1,2,3].sum());
trace(["joe", " ", "mckenzie"].sum());

Array.prototype.select = function(f) {
	var n = [];
	this.map(function (x) {if (f(x)) {n[n.length] = x}});
	return n
}

trace([1, 2, 3, 4].select(function(x) {return x > 2}));

// >> 3, 4

Array.prototype.scan = function(f) {
	var n = [];
	this.map(function(x) {n[n.length] = f(n[n.length-1], x)});
	return n
}

// k: +\2 4 6
trace([2,4,6].scan(sum));
// >> 2, 6, 12