But yes, your way is great as well. I was really just trying to shed some light on the reasons why the OP's (and my) original ways weren't working, so was avoiding the prototype magic.
On 9/7/06, Brandon Aaron <[EMAIL PROTECTED]> wrote:
Shouldn't something like this work and provide more meaning:
var stars = $('star1', 'star2', 'star3', 'star4', 'star5');
stars.each(function(star, num) {
star.observe('click', function(e){objRating.setRating (num);});
});
That of course is with the 1.5_rc1 of prototype and it is untested.
Brandon
On 9/7/06, Chris Lear <[EMAIL PROTECTED]> wrote:
>
> * Ryan Gahl wrote (07/09/06 15:42):
> > What Eric was saying was not that they are all using the same callback,
> > but that they are all referencing the same i variable at the same
> > address in memory, which at the end of your loop holds the value 6. You
> > would have been fine if you had created a locally scoped variable new_i
> > within the loop and used that in the callback (of course Eric's
> > alternative also works fine, but I'm just trying to clear this issue up
> > a little in your mind so you know next time)
> >
> > This would have worked:
> >
> > for (var i=1; i<=5;i++){
> > var new_i = i;
> > Event.observe ($('star'+new_i), 'click',
> > function(e){objRating.setRating(new_i)});
> > }
>
> I don't think even this works. new_i is in the same scope. When I tried
> it, I got all 5s (rather than 6s), which would correspond to all the
> closures using one value for new_i - the last one assigned.
> Variable scoping in closures is hard (for me, anyway) to get to grips
> with, so I don't think I'll try an explanation - probably Ryan could doo
> better than me anyway.
>
> These should both work, and are viable alternatives to Eric's solution:
>
>
> // Solution One (simplest case of returning a closure from a function)
>
> for (var i=1; i<=5;i++){
> Event.observe($('star'+(x)), 'click', myfunc(i));
> }
> // Return the closure from a new function that uses a variable in local
> // scope
> function myfunc(x) {
> return function(e){objRating.setRating(x)}
> }
>
>
> // Two
> // Use the prototype bind function to bind the "this" variable
> for (var i=1; i<=5;i++){
> Event.observe(
> $('star'+(x)),
> 'click',
> function(e){objRating.setRating(this)}.bind(i)
> );
> }
>
> Eric's solution does the same thing, but hides the detail behind more
> prototype cleverness.
>
> Apologies if I've transcribed these wrong. They worked in a test page I
> made, but I just used alerts rather than objRating.setRating etc.
>
> This is all a bit academic considering that the OP says he's happy now,
> but I find closure code fascinating. I also find the bind() and
> bindAsEventListener() methods to be some of the best things about prototype.
>
> Chris
>
> >
>
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-~----------~----~----~----~------~----~------~--~---
- [Rails-spinoffs] Re: Event.observe problems Ryan Gahl
- [Rails-spinoffs] Re: Event.observe problems Chris Lear
- [Rails-spinoffs] Re: Event.observe problems Matt Jones
- [Rails-spinoffs] Re: Event.observe problems Ryan Gahl
- [Rails-spinoffs] Re: Event.observe problems Matt Jones
