On Fri, 11 Feb 2011, Igor Stasenko wrote:
On 11 February 2011 02:28, David T. Lewis <[email protected]> wrote:
We had a good deal of discussion earlier about adding Object>>is:
with an inconclusive outcome:
http://lists.squeakfoundation.org/pipermail/squeak-dev/2010-April/148501.html
Igor's original proposal is:
http://lists.squeakfoundation.org/pipermail/squeak-dev/2009-June/136793.html
I have been tinkering around with Juan's SimpleMorphic in hopes of
getting it running in Squeak alongside MVC and Morphic, and it would
be convenient to have the default implementation of #is: in the image
so I don't have to put it in a package override.
Just yesterday i had discussion about this with people in the lab. I
can't say that i heard something new regarding this,
and not saying that i'd like to resurrect the discussion.
So, in short: there was no objection concerning getting rid of isXXX
in favor of using #is: method.
What about performance?
The only thing which still looks controversial is too simple default
implementation which answers false.
To my current opinion, Juan's variant is preferable. :) Yes. it should
answer false and don't contain any extra logic , like trying to follow
class hierarchy etc.
Because it serves to replace isXXXX pattern, and not adding something
new (i.e. more 'userful'). So, answering false for Object class fits
well for this purpose.
And of course solution to that problem is simple:
- avoid writing code in style, which require isXXX tests and then
branching. Nicely written code should use message dispatch instead.
Too bad, we are not living in perfect world :)
Is it better to flood superclasses with no-op extension methods?
Levente
Any strong objections?
--
Best regards,
Igor Stasenko AKA sig.
