Hi Alex,

On Sat, Jul 25, 2015 at 10:02 PM, Alexandre Bergel <alexandre.bergel@me.com> wrote:

Hi Peter!

> Basically I want to have either:
> a) option to execute behavior when element is added to view --- this is basically direct counterpart to TRRemovedCallback.
>
> So I could do things like...
>
> element addCallback: (TRAddedCallback: [ :shape | "add dependent elements or whatever" ]).

Sure, easy. I have just committed this. Update Trachel and you can do (this is a test I wrote):

Excellent, thank you!

> b) have RTInteractions be lazily initialized --- only after the element has been added to the view.
>
> (or both)

This is a bit more problematic. I am not sure about it.

> The idea is to have more clearly resolvable interactions like RTLabelled, which currently requires for the element to be already in the view.
> I'm not sure if the second option will be entirely feasible, because many of the interactions are stateless and require immediate evaluation... but that could be resolved with some flags or different subclassing or something...
>
> Is it possible for you? Is this something you want in Roassal?

Are these lazy interactions something you need just for the added callback? Or is it something you need for other needs?

TRAddedCallback is generic so I can easily use it for lazy interactions...

imagine for example

RTLabelled>>initializeElement: anElement

anElement view

ifNil: [ anElement addCallback: (TRAddedCallback: [ :evt | self lazyInitializeElement: anElement ]) ]

ifNotNil: [ self lazyInitializeElement: anElement ]

and then you can remove the el view ifNil: [ self error: 'You are trying to use RTLabelled ].error checking.

So TRAddedCallback is good for both scenarios.

Thank you!!

Peter