[squeak-dev] Re: NanoTraits are go

Andreas Raab andreas.raab at gmx.de
Wed Dec 30 13:35:22 UTC 2009

David T. Lewis wrote:
> The only thing that I would want to check - and apologies for my ignorance
> here - is backward compatibility with regards to image segments. My
> recollection is that Squeak 3.9 broke all kinds of things, including
> SqueakMap and EToys projects, as a result of incompatibilities associated
> with the introduction of traits into the image. So I would just want to
> make sure that NanoTraits does not introduce further incompatibilities
> that might make it more difficult to support EToys projects in the future.

Yes, a very good point. The changes that I'm making make Etoys and 
Squeak *more* compatible, not less. As Igor was pointing out I have been 
pushing various bits of state that were scattered around all over the 
places (in some cases duplicated in *three* places) into separate 
entities: TraitOrganizer and TraitMethodState. Those are only used when 
you actually use traits, and as a consequence, when you don't use traits 
the structure is identical to Etoys and consequently image segments will 
work fine.

So at least this level of incompatibility will cease to exists. Oh, and 
score one more point for delegation over inheritance.

   - Andreas

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