[GOODIE] Squeak Smalltalk: A Quick Reference (v. 0.0)
Marcus Denker
marcus at ira.uka.de
Sun Dec 5 20:01:47 UTC 1999
On Sun, Dec 05, 1999 at 02:32:05PM -0500, Andrew C. Greenberg wrote:
> >ProtoObject is the real root of the class hierarcy, and Object is
> >actually a subclass of ProtoObject. ProtoObject represents the
> >"behaviourless object" -- the absolute minimum that is required to
> >exist "harmoniously" as an object in the image.
>
>
> Of course, ProtoObject does have behavior. It responds, in particular, to:
>
> #isNil
> #ifNil:ifNotNil (and friends)
> #pointsTo:
> comparison for identity
> become:
> nextInstance
> nextObject
> rehash
>
> so, like nil, ProtoObject isn't a "pure" abstraction of
> behaviorlessness. Couldn't we handle #doesNotUnderstand: a bit more
> graciously without practical harm?
>
Yes, I think this can be done. As Ian noted every subclass of ProtoObject
has to implement #doesNotUnderstand, so we can add it to ProtoObject
without a problem. (And I should have done this right in the original
ProtoObject-changeset).
Marcus
--
Marcus Denker marcus at ira.uka.de phone at home:(0721)614235 @work:(0721)608-2749
Imitating paper on a computer screen is like tearing the wings off a 747 and
using it as a bus on the highway. -- Ted Nelson
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