[Laszlo-dev] how do I check for the existence of an attribute?

[Sarah Allen]

I notice that there is a capabilities property in the v4 doc for view  
(but no description):
http://www.openlaszlo.org/lps4/docs/reference/LzView.html

but not in the 4.2 doc:
http://www.openlaszlo.org/lps4.2/docs/reference/

It sound promising though...

Sarah

On Feb 10, 2009, at 5:57 AM, Sarah Allen wrote:

> what is a views 'capabilities' list?
>
> On Feb 10, 2009, at 4:32 AM, P T Withington wrote:
>
>> Shouldn't the existence of a microphone be in the view's  
>> `capabilities` list?
>>
>> On 2009-02-09, at 21:34EST, Max Carlson wrote:
>>
>>> Videoview.mic could be initialized to false and you could test for  
>>> that value explicitly, to differentiate against null.
>>>
>>> I'll try that with the change you sent me for review...
>>>
>>> Sarah Allen wrote:
>>>> The microphone has the following code:
>>>>          // Use duck typing to check for the existence of the
>>>>          // _setMic method, instead of checking if the
>>>>          // immediateparent is an instance of videoview, to avoid
>>>>          // loading the videoview class if it's not needed.
>>>>          if (immediateparent['_setMic']) {
>>>>              immediateparent._setMic(this);
>>>>          }
>>>> This doesn't work because videoview no longer has a setMic  
>>>> method.  Instead, we're supposed to use setAttribute...
>>>> However, then we would need to write:
>>>>          if (immediateparent['mic']) {
>>>>              immediateparent.setAttribute('mic', this);
>>>>          }
>>>> except that won't work since mic is intialized to null and  
>>>> immediateparent['mic'] will evaluate to false.
>>>> Any syntax gurus in the house?
>>>> Thanks,
>>>> Sarah
>>>
>>> -- 
>>> Regards,
>>> Max Carlson
>>> OpenLaszlo.org
>>
>