Function guard

guard.js:29–37

* Creates a guarded version of f that can only be entered when the supplied * condition allows. * @param {function} condition represents a critical section that may only * be entered when allowed by the condition * @param {function} f function to guard * @returns {function} guarded versio

(condition, f)

	 * @returns {function} guarded version of f
	 */
	function guard(condition, f) {
		return function() {
			var args = slice.call(arguments);

			return when(condition()).withThis(this).then(function(exit) {
				return when(f.apply(this, args))['finally'](exit);
			});
		};
	}

	/**
	 * Creates a condition that allows only n simultaneous executions