Instance-specific behavior question (like Ruby?)
bert at impara.de
Tue Mar 23 11:04:32 UTC 2004
Am 23.03.2004 um 09:00 schrieb Poster at Kinetium dot Com:
> I am somewhat familiar with the idiom of doing instance specialization
> overriding "doesNotUnderstand".
> Ruby provides a different and more direct way of doing such prototype
> programming: it simply makes the instance belong to a new (anonymous)
> and puts any instance-specific behavior on that class. It provides a
> to define that behavior (since the class is anonymous).
> Is there a way to do this in Squeak? I'm a relative Squeak newbie ...
Yes, this is how the instance-specific methods in the Etoys environment
are realized. Objects start out as instances of UnscriptedPlayer. As
soon as you add a script, the object is transformed (see
#assureUniClass) int a unique subclass of Player, and the script is
added to this instance.
There is no special syntax for it, but you have to do a bit of "meta
programming". You send #instanceOfUniqueClass to any class to get an
instance of, you guessed it, a unique subclass. Then you can compile
any method into this instances class, and have high-performance
- Bert -
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