recursed-timeout-action.js

/* GIVEN: <div id='foo' /> such that out := $('#foo')
*/

/* Enclosed code block (anonymous namespace) for execution */
(function(){

  /* Wait times for window.setTimeout in seconds */
	var times = [0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,1,1.5,2.0];
	
	/* This is so that we have a stopping point to avoid infinite recursion
	  Because of the way this is designed, it could cause a browser to halt */
	var count = 1, maxCount = 1000;
	
	/* The action that will be taken each time */
	var action = function(s){
		if(s){
			out.append("Waited " + s + " seconds<br />");
		} else {
			out.append("Done!");
		}	
	};
	
	/* Build our queue FILO style ( displays "Done!" ) */
	var recursedTimeoutAction = function(){ action(); };
	
	/* Create a tail-recursive queue 
	(should be equiv to regular for loop)*/
	for(var i = times.length-1; i > -1; i--){
		var currentTime = times[i];
		
		/* Set global recursedTimeoutAction to itself 
		(in present state) executing current action */
		recursedTimeoutAction = (function(recursedCurrent, currentTime){
		
			/* Return a new function containing an execution against
			the current value of recursedTimeoutAction as enclosed via
			recursedCurrent */
			return function(){
				// Do not execute until we've passed currentTime seconds
				window.setTimeout(
					function(){
						// Display currentTime
						action(currentTime);
						
						/* NOTE: If we've gone to many times, break out. This is 
						handy if you edit this code and screw up, otherwise
						you will halt your browser and possibly your computer
						(stack overflow).*/
						if(count < maxCount){
							count++;
							recursedCurrent(currentTime);
						} else { 
							alert("ERROR: WENT THROUGH TOO MANY RECURSIONS"
								+ " &mdash; Recursion limit = " + maxCount); 
						}
					}, 
				currentTime*1000);
			};
		}(recursedTimeoutAction, currentTime));
	}
	
	/* Finally, call what we've built */
	recursedTimeoutAction(0);

}()); /* Execute this entire closure */