Thanks for the thorough reply.
On Sep 27, 6:13 am, "T.J. Crowder" wrote:
> Hi,
>
> > The author of coffeescript mentioned on this thread (http://github.com/
> > jashkenas/coffee-script/issues/issue/675/#issue/675/comment/402197)
> > that ie leaks memory if you use named functions, instead of closures.
>
> IE doesn't leak memory if you use named functions (or at least, I've
> never heard of it doing so). I'm pretty sure jashkenas was talking
> about a bug IE has related to named function *expressions*, which are
> a different thing. Prototype doesn't use any named function
> expressions.
>
> Here's a named function declaration:
>
> function foo () {
>
> }
>
> Here's a named function *expression*:
>
> var f = function foo() {
>
> };
>
> The difference being that you're using the function as a right-hand
> value in an expression. (A right-hand value is the value to the right
> of an = in an assignment, to the right of a : in a property
> initializer, or that you pass into a function when calling it.)
>
> The short version of the bug is that IE will create two near-identical
> functions instead of one if you use a named function expression. This
> is wrong, and of course it means that IE uses double the memory it
> should have, but it isn't a memory "leak" in the sense of ever-
> increasing memory usage. Another aspect of the bug is that the symbol
> `foo` gets defined in the containing scope, which is incorrect.
>
> For more details, it happens that I just recently wrote this up
> (although the bug has been around
> forever):http://blog.niftysnippets.org/2010/09/double-take.html
>
> IE isn't the only browser that has (or has had) issues with named
> function expressions. kangax wrote up a very useful article a while
> back on what NFEs are and how they get treated by various versions of
> various JavaScript engines. The article is a couple of years old now
> and the most recent implementations of many engines do better, though
> not IE's JScript:http://kangax.github.com/nfe/
>
> Slightly off-topic, but you said "...named functions, instead of
> closures...". Named functions *are* closures. Whether the function
> has a name doesn't affect whether it closes over data. More about
> closures
> here:http://blog.niftysnippets.org/2008/02/closures-are-not-complicated.html
>
> HTH,
> --
> T.J. Crowder
> Independent Software Engineer
> tj / crowder software / com
> www / crowder software / com
>
> On Sep 27, 3:01 am, Daniel Ribeiro wrote:
>
> > The author of coffeescript mentioned on this thread (http://github.com/
> > jashkenas/coffee-script/issues/issue/675/#issue/675/comment/402197)
> > that ie leaks memory if you use named functions, instead of closures.
> > If this is true, why does Prototype uses some of these (such as
> > function $A onhttp://prototypejs.org/assets/2009/8/31/prototype.js)?
--
You received this message because you are subscribed to the Google Groups
"Prototype & script.aculo.us" group.
To post to this group, send email to prototype-scriptacul...@googlegroups.com.
To unsubscribe from this group, send email to
prototype-scriptaculous+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/prototype-scriptaculous?hl=en.
