David Harris has a brief post about the joys of jQuery where he comments on what, to him, was an unexpected feature that allowed binding of variables, i.e., JavaScript (and ActionScript) support closures. I find it interesting that he thinks this binding "somehow feels wrong" and I've seen the same reaction from a number of people when first confronted with closures.
This binding is what gives closures their power and why they are more than just "anonymous functions". They carry with them the context in which they were created.
It's also an interesting contrast with ColdFusion where variable binding is done at the last minute at runtime and thus you can take a UDF function that references variables.foo (which might be a page scope variable) and add that function to a CFC instance and now variables.foo will refer to foo in the variables scope of the CFC itself.
I think that's why my Closures for CFMX library has proved so puzzling for a lot of folks :)
I'm conserned that they might pose a memory leak when used often. SInce there is no reference to it, how can it be garbage collected. I can add an event listener for the closure's parent function, but I can't unregister that listener.
Any ideas?
Perhaps it's not an issue for a function rarely called, but I was using it with an enterFrame event and I was unable to stop the event from being called by using a removeEventLListener(Event.ENTER_FRAME, (my function with closure).
Because I was only refering to the enter frame function Indirectly ( only through a parent function) it seemed odd.
Do am I incorrect anywhere?
Thanks
Sergio
http://corfield.org/search/closures
I have a friend who is much more clued up on AS3 who gave me some feed back telling me not to use anon functions in AS3.
I'll check up why again and do a follow up blog post, so keep an eye on my blog :-)
