peterhil/range.js

## range.js
// JavaScript Range Function

// © 2006 Matthias Miller (originally written March 29, 2006)
// © 2010-2011 Peter Hillerström (modified 20.10.2010)

// Feel free to use it under the BSD license.

// Version: 0.1 Matthias Miller (originally written March 29, 2006)
// Version: 0.2 Peter Hillerström (modified October 20, 2010)
// Version: 0.3 Peter Hillerström (rewritten on May 24, 2011)

// Original found on Matthias’ blog entry:
// http://outofhanwell.wordpress.com/2006/03/29/javascript-range-function/

// Sometimes I get hit by random thoughts in the middle of some programming changes.
// Have you ever wanted to write code like this?
//
// for (var i in range(12)) ...
// or:
// for (var i in range(-10,11,5)) ...

function sign(x) {
    return x/Math.abs(x) || 0;
}

function range(/*[start,] end[, step]*/) {
    var a = Array.prototype.slice.call(arguments),
        start   = (a.length === 1) ? 0 : a[0],          // when given only one argument: start from 0,
        end     = (a[1] !== undefined) ? a[1] : a[0],   // and default end to the first argument
        step    = (a[2] !== undefined) ? a[2] : 1,      // default to 1
        cur     = start,
        result  = [];

    step = Math.abs(step) * sign(end-start);        // Normalize the step direction
    if (Math.abs(step) > Math.abs(end-start)) {     // Step can't be larger than the interval
        return result;
    }

    do {
        result.push(cur);
        cur += step;
    } while (sign(step)*(cur-start) < sign(step)*(end-start));

    return (sign(a[2]) === -1) ? result.reverse() : result;
}
	// JavaScript Range Function

	// © 2006 Matthias Miller (originally written March 29, 2006)
	// © 2010-2011 Peter Hillerström (modified 20.10.2010)

	// Feel free to use it under the BSD license.

	// Version: 0.1 Matthias Miller (originally written March 29, 2006)
	// Version: 0.2 Peter Hillerström (modified October 20, 2010)
	// Version: 0.3 Peter Hillerström (rewritten on May 24, 2011)

	// Original found on Matthias’ blog entry:
	// http://outofhanwell.wordpress.com/2006/03/29/javascript-range-function/

	// Sometimes I get hit by random thoughts in the middle of some programming changes.
	// Have you ever wanted to write code like this?
	//
	// for (var i in range(12)) ...
	// or:
	// for (var i in range(-10,11,5)) ...

	function sign(x) {
	return x/Math.abs(x) \|\| 0;
	}

	function range(/[start,] end[, step]/) {
	var a = Array.prototype.slice.call(arguments),
	start = (a.length === 1) ? 0 : a[0], // when given only one argument: start from 0,
	end = (a[1] !== undefined) ? a[1] : a[0], // and default end to the first argument
	step = (a[2] !== undefined) ? a[2] : 1, // default to 1
	cur = start,
	result = [];

	step = Math.abs(step) * sign(end-start); // Normalize the step direction
	if (Math.abs(step) > Math.abs(end-start)) { // Step can't be larger than the interval
	return result;
	}

	do {
	result.push(cur);
	cur += step;
	} while (sign(step)(cur-start) < sign(step)(end-start));

	return (sign(a[2]) === -1) ? result.reverse() : result;
	}