[Laszlo-dev] how do I implement a mixin as in LZX?

[Sarah Allen]

Raju,

That makes sense.  Max and I are working to get them to be more normal  
LZX syntax now that swf9 is fully supported.

Sarah

On Jan 18, 2009, at 6:46 PM, Raju Bitter wrote:

> Sarah,
> there's a simple reason that JS2 syntax was used in the AV  
> components. At the time when I converted the code to JS2 that only  
> way to pass the AS3 import statements into a class. The #passthrough  
> { }# directive - which can be used inside an LZX based class right  
> now - wasn't available back then.
>
> I based the AV classes on the drawview.lzx code, copying the mixin  
> code into the AV classes. I never finished the work last year and  
> passes the classes on to Max, since I was buried in work at that time.
>
> - Raju
>
>> I guess I don't really understand why they were used in the a/v
>> extensions.  I'll take Max's word for it that the mediastream
>> implementation does nothing and remove the mixin there.
>>
>> On Jan 9, 2009, at 8:44 AM, P T Withington wrote:
>>
>> > Note that mixin's are a 'power feature'.  I consider them to still
>> > be experimental, which is why the documentation is scarce.  I don't
>> > want them to be public, because I am not ready to commit to
>> > supporting them.
>> >
>> > Also note that a <mixin> is very different from a `mixin`.  That  
>> is,
>> > the LZX version is quite different from the JS version.  The JS
>> > version is pretty much a standard implementation of what CS would
>> > consider a mixin (which is in CS considered a dangerous power tool,
>> > not to be used lightly -- it's why Java and C# don't have them).
>> > The LZX version is even crazier, because _I_assume_ an LZX mixin
>> > needs to know how to mix in child nodes, states, placement,
>> > handlers, constraints, etc., etc., etc. which are not something you
>> > have in a plain old O-O language.
>> >
>> > Bottom line:  mixins are an optimization and you should follow my
>> > usual rules about optimization when considering them:
>> >
>> > Rule 1:  Don't use them.
>> > Rule 2 (for experts only):  Don't use them yet.
>> >
>> > (paraphrased from M. A. Jackson)
>> >
>> > On 2009-01-09, at 07:50EST, Max Carlson wrote:
>> >
>> >> Since that mixin isn't really doing anything, you should be able  
>> to
>> >> just get rid of it.  See tests/mixin for an example of how to do
>> >> this in LZX, or http://jira.openlaszlo.org/jira/browse/LPP-2302  
>> for
>> >> the gory details.
>> >>
>> >> Once we get all the code converted back to LZX syntax, we might
>> >> want to add a mixin that implements the runtime-specific bits.
>> >>
>> >> Sarah Allen wrote:
>> >>> I'm refactoring the av mediastream component to be regular LZX,
>> >>> but I'm not familiar with the mixin syntax and I can find
>> >>> documentation about (no luck with google or the ref guide...  
>> maybe
>> >>> I'm blind)
>> >>> Here's the snippet that I want to write the "new" way...
>> >>> <script when="immediate"><![CDATA[
>> >>>   mixin NewmediastreamShared {
>> >>>       function NewmediastreamShared ( parent:LzView? = null ,
>> >>> attrs:Object? = null , children:Array? = null,  
>> instcall:Boolean  =
>> >>> false) {
>> >>>           super(parent, attrs, children, instcall);
>> >>>       }
>> >>>   }
>> >>> ]]></script-->
>> >>> (Trying to avoid that nasty setter bug, which I think is at the
>> >>> root of why recording is broken)
>> >>> Sarah
>> >>
>> >> --
>> >> Regards,
>> >> Max Carlson
>> >> OpenLaszlo.org
>> >