[Laszlo-dev] Should this code go into the SWF runtime?

[P T Withington]

Right, but what Henry was proposing was for their to always be an  
event object created.  Then you would never have to check for the  
event object existing (so the idiom you use would go away).

BUT, Jim discovered that, at least on the swf runtime, because  
function calls are relatively expensive, that testing for the  
delegateList being empty or not before calling sendEvent saved  
considerable time, at least with very frequent events (in particular  
onwidth and onheight).

The best of all worlds would be for sendEvent to be inlined, at least  
to the point of checking the delegateList, and only call the out-of- 
line helper function when there are delegates listening.  For now,  
that would have to be done by special code in the compiler...

On 2006-04-12, at 00:29 EDT, Sarah Allen wrote:

> In the component code and application code that I've been creating,  
> it is common to write:
>   if (foo.someevent)  foo.someevent.sendEvent()
>
> This avoids debugger warnings if no one is registered for someevent.
>
> Sarah
>
>
> On Thu, Apr 6, 2006 at  9:01 PM, P T Withington wrote:
>
>> Belay that.  Not sure what I was thinking here.
>>
>> It would be an optimization to not call sendEvent if the event's  
>> delegateList was empty.  At least in the swf runtime, where  
>> function calls are costly.
>>
>> But I'm not sure this is the whole answer.  It looks like you are  
>> trying to create some sort of 'null' event for each declaration.   
>> If you do this, you also need to check for this null event when  
>> you do add a delegate (and convert it into a real event).
>>
>> On 2006-04-06, at 20:38 PDT, Henry Minsky wrote:
>>
>>> So that needs  to be a convention that everyone obeys when they  
>>> write calls
>>> to sendEvent? Not just in the LFC, I'm just thinking about user  
>>> code, if app
>>> developers are going to be told to do
>>>
>>> if (foo.someevent)  foo.someevent.sendEvent()
>>>
>>> instead of
>>>
>>> foo.someevent.sendEvent()
>>>
>>>
>>> Or is there some kind of magic we could use to do this   
>>> automatically ?  I
>>> guess it would need to be some kind of macro processor :-)
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> On 4/6/06, P T Withington <ptw at openlaszlo.org> wrote:
>>>>
>>>> If you do, annotate LPP-1915 to say this can be removed when all
>>>> callers of sendEvent check for no listeners first (which should be
>>>> much more efficient than making a call to the empty function).
>>>>
>>>> On 2006-04-06, at 19:56 PDT, Henry Minsky wrote:
>>>>
>>>>>
>>>>> This code for declaring events is currently in the DHTML runtime
>>>>> but not in the SWF runtime.
>>>>>
>>>>> Should this go into the SWF runtime as is, or is there anything we
>>>>> need to do differently?
>>>>>
>>>>> [background for the viewing audience; we need to avoid referencing
>>>>> properties of null values
>>>>> in the DHTML runtime, as it brings the browser javascript
>>>>> interpreter to a screeching halt]
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> LzDeclaredEvent = {};
>>>>> LzDeclaredEvent.sendEvent = function ( a ){  return a };
>>>>> LzDeclaredEvent.toString = function ( ){
>>>>>     return "Declared event";
>>>>> }
>>>>>
>>>>> function DeclareEvent( who , what ){
>>>>>     //    debug('declare ' + who + ' what ' + what);
>>>>>     who[ what ] = LzDeclaredEvent;
>>>>> }
>>>>> function DeclareEvents( who , what ){
>>>>>     //    debug('DeclareEvents', who, what);
>>>>>     for (var i in what) {
>>>>>         //info('what', what[i]);
>>>>>         who[what[i]] = LzDeclaredEvent;
>>>>>     }
>>>>> }
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Henry Minsky
>>>>> Software Architect
>>>>> hminsky at laszlosystems.com
>>>>>
>>>>> _______________________________________________
>>>>> Laszlo-dev mailing list
>>>>> Laszlo-dev at openlaszlo.org
>>>>> http://www.openlaszlo.org/mailman/listinfo/laszlo-dev
>>>>
>>>>
>>>
>>>
>>> --
>>> Henry Minsky
>>> Software Architect
>>> hminsky at laszlosystems.com
>>
>> _______________________________________________
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>> Laszlo-dev at openlaszlo.org
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>