[Laszlo-dev] how to handle user-defined classes in the swf9 runtime

Mon Jan 7 14:30:28 PST 2008

It was already filed in JIRA as:
   http://www.openlaszlo.org/jira/browse/LPP-5266

It's marked for Devildog, possibly it needs to be more encompassing  
than that.

I just added the recent emails as comments to the JIRA.

On Jan 7, 2008, at 4:31 PM, P T Withington wrote:

> We have a plan!
>
> A _mixin_ (we need to update our terminology) is really just an  
> _interface_ with implementation.  The JS2 back end, when it sees a  
> mixin has to remember the implementation, and has to emit an  
> interface declaration (i.e., copy the declaration through, stripping  
> out any implementation -- actually, initially, it could leave out  
> the body altogether I think).  Then, for each class that uses that  
> mixin:
>
>  mixin amixin { <body of amixin> };
>
>  mixin bmixin { <body of bmixin> };
>
>  class aclass extends anotherclass with amixin, bmixin { <body of  
> aclass> };
>
> the compiler has to emit 'interstitial' classes:
>
>  interface bmixin {};
>
>  class lzsc::bmixin$anotherclass extends anotherclass implements  
> bmixin {
>    <body of bmixin>
>  };
>
>  interface amixin {};
>
>  class lzsc::amixin$bmixin$anotherclass extends lzsc::bmixin 
> $anotherclass implements amixin {
>    <body of amixin>
>  }
>
>  class aclass extends lzsc::amixin$bmixin$anotherclass implements  
> amixin, bmixin { <body of aclass> }
>
> Don, if we don't have a task filed for this, please file one.
>
> On 2008-01-07, at 16:08 EST, Henry Minsky wrote:
>
>> So what should we do with traits, I wonder.
>>
>>
>> On Jan 7, 2008 3:36 PM, P T Withington <ptw at pobox.com> wrote:
>>> Remember Class.lzs is really just the runtime support for JS2 class
>>> semantics in a JS1 runtime.  So the goal is to have that be unused  
>>> in
>>> a JS2 runtime (like swf9).
>>>
>>>
>>> On 2008-01-07, at 15:34 EST, P T Withington wrote:
>>>
>>>> I agree.
>>>>
>>>> I'm just not sure if we need a UserClass (that is a subclass of
>>>> view) that these classes inherit from, or if they can just directly
>>>> inherit from view (or some other lfc class).  There is some stuff
>>>> that happens in UserClass that is different from node.
>>>>
>>>> On 2008-01-07, at 15:30 EST, Henry Minsky wrote:
>>>>
>>>>> I think the most pragmatic thing to do is to bite the bullet, so  
>>>>> to
>>>>> speak, and make
>>>>> the tag compiler emit class { .... } declarations for user-defined
>>>>> classes. It seems like
>>>>> the alternative would be to use our Class.lzs in swf9 for user-
>>>>> defined classes
>>>>> at runtime, which seems like it would cause all sorts of  
>>>>> confusion.
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Henry Minsky
>>>>> Software Architect
>>>>> hminsky at laszlosystems.com
>>>>
>>>
>>>
>>
>>
>>
>> -- 
>> Henry Minsky
>> Software Architect
>> hminsky at laszlosystems.com
>

--

Don Anderson
Java/C/C++, Berkeley DB, systems consultant

voice: 617-547-7881
email: dda at ddanderson.com
www: http://www.ddanderson.com