simple namespace

/*
 * ns('foo.bar'); 
 *   => window.foo = {bar: {} };
 * ns('some.arbitrary.depth.string');
 *   => window.some = {arbitrary: {depth: {string: {} } };
 * ns('some.other.ns');
 *   => window.some is already created, so window.some.other = {ns: {}};
 */
function ns( str, root )
{
    var parts = str.split('.'),
        part, ndx = -1,
        len = parts.length;

    root = root || this;

    while (++ndx < len) {
        part = parts[ndx];
        if (!(part in root)) root[part] = {};
        root = root[part];
    }

    return root;
}​