[squeak-dev] USe of isKindOf: is a crime against humanity

Casey Ransberger casey.obrien.r at gmail.com
Sun Sep 1 03:30:20 UTC 2013


Totally. Also, one might argue that switching on type isn't terribly
object-oriented. Or rather, it sort of re-implements dispatch. Sometimes
it's hard to avoid, but some hard things are worth doing. Of course I'm a
big fat hypocrite once in a long while (DNU hacks, #isKindOf:, etc.)

#respondsTo: is nicer in some spots. Protocol isn't class. Etc.

+1


On Sat, Aug 31, 2013 at 7:39 PM, tim Rowledge <tim at rowledge.org> wrote:

> There are 623 senders of isKindOf: in the 4.5 image I'm using right now -
> which may be more than the general because I have some extra stuff loaded -
> and I'd bet that there are no more than a dozen places where it is actually
> a sensible way of doing what is needed.
>
> It's slow - it scans up a class tree.
> It's ugly.
> It isn't actually testing what a lot of people seem to think - if you want
> to find out is some object can handle a certain capability try actually
> asking with something like  #isAGraphicThing rather than (isKindOf: Morph)
> or:[ foo isKindOf: DisplayObject] blahblahblah.
>
> We can do better.
>
> tim
> --
> tim Rowledge; tim at rowledge.org; http://www.rowledge.org/tim
> Useful random insult:- Paralyzed from the neck up.
>
>
>
>


-- 
Casey Ransberger
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