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

Mon Jan 7 13:31:42 PST 2008

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