Multiplayer WORKS! (separate instances updating through the database)

Joe gave me permission to make the blog posts short and sweet.  I'm going to try to keep this one more at an overview level.

The goal I set out to accomplish was to separately run multiple instances (i.e. one per player) of the swf with each one keeping itself updated on the actions made (turns taken) by the others.

How it works:

• In the HTML for the embed/object elements, the FlashVars parameter provides (a) the total number of players in the game, and (b) with which player number that particular swf instance is to be associated.
• As the "whole document" class (TraceRace) is a DisplayObject, its Actionscript constructor uses its LoaderInfo instance to grab the values of the FlashVars.
• When it's a player's turn, that swf will both show and allow clicking on the options for the next turn.  Upon the click of an option, the URLVariables/URLLoader/etc. classes send off this data to a PHP handler script, which sends a MySQL query to input a row in the database table.
• When it's not a player's turn, that swf will show the other player's turn options, but they are not clickable (so that you can't go taking someone else's turn).  The swf uses the same URL[whatever] classes to poll for other players' turns showing up in the database: every two seconds, a POST is made which is handled by a PHP script.  If the script returns the other player's turn data (since it has been entered in the database), it stops polling, and this swf updates the other player's move visually and in its own state (variables).  If the other player's turn has not been entered into the database yet, the script just returns a boolean indicating such, and it initiates the next polling request.

Problems:

• After I thought I'd figured them out last time, turned out I still was having issues with booleans.   I'm now sending booleans through PHP echoes as 1 (true) or 0 (false), because the AS can easily convert them to actual booleans, whereas the word strings "true" and "false" are not so easily converted.
• During debugging I ended up trying to be pretty precise with types, even though I'm not always sure if that was causing a bug or not.  For example, I cast variables parsed from PHP-echoed name/value strings to, say, a Number or a uint.  I also cast a piece to a piece when I pull it out of an array, since I don't think arrays are designated to hold a certain single type.
• It looks like AS isn't happy with my passing an argument as 'null' (since I was going to retrieve the necessary object a different way, once inside the function).  Then I tried using two parameters with default values, but since you can only leave out arguments at the end of the list, I can't input the 2nd and drop the 3rd in one call while doing the reverse in another call.  Eventually I just wrote a getter function so I could access the object before the problematic call.
• One of the weirdest problems I've had yet, I actually managed to create myself.  By initializing an Array with a specific length, and subsequently pushing more elements into it, I ended up with empty spaces prior to the pushed elements.  This actually makes pretty decent sense.  But since previously I hadn't initialized the array with a length, the pushed elements just added/filled spots from the beginning.  I finally realized what was going on and now add the elements by accessing the array slots via indices.

Now for the cool part.  I took a screencast video (thanks Screencast-O-Matic!!!) to show how this actually all operates in my testing setup.