I just read the Wikipedia article on closures[1] today and learned quite a
bit myself (which isn't saying much!). I would recommend it to anyone
wanting to learn more about it. To quote a portion:
"[...] a closure is a semantic concept referring to a function paired with
an environment [...] Typically, a closure occurs when one function appears
entirely within the body of another, and the inner function refers to local
variables of the outer function. At runtime, when the outer function
executes, a closure is formed, consisting of the inner function's code and
references to any variables of the outer function required by the closure
[...] "
[1] http://en.wikipedia.org/wiki/Closure_%28computer_science%29
On 4/18/07, Rob Desbois <[EMAIL PROTECTED]> wrote:
17By creating a function form your code which uses variables outside its
scope, you've created a 'closure'.
When settings.functionToCallLater() is called after init() has finished,
aVariable has gone out of scope. The function still has access to it
however, because the closure consists of two parts: the code of the function
itself, and a reference to all variables outside its scope that it needs
access to.
Have a search on Google for 'javascript closures', there are plenty of
good articles that can explain this more fully than me.
HTH,
rob
On 4/18/07, Ariel Jakobovits <[EMAIL PROTECTED]> wrote:
>
>
> this isn't the real code, just a mockup, but ...
>
> can someone explain to me why this works (as in, alert echoes 'ariel'):
>
> var temp = null;
>
> function init ()
> {
>
> var aVariable = 'ariel';
>
> var settings = {
> functionToCallLater: function (content) {
> alert(aVariable);
> }
> };
>
> temp = new anotherClass(settings);
> }
>
> anotherClass.callThatFunction ();
>
>
>
>
--
Rob Desbois
Eml: [EMAIL PROTECTED]
Tel: 01452 760631
Mob: 07946 705987
"There's a whale there's a whale there's a whale fish" he cried, and the
whale was in full view.
...Then ooh welcome. Ahhh. Ooh mug welcome.
