[Pharo-project] [squeak-dev] Object>>is:

Levente Uzonyi leves at elte.hu
Fri Feb 11 02:51:26 CET 2011

On Fri, 11 Feb 2011, Igor Stasenko wrote:

> On 11 February 2011 02:28, David T. Lewis <lewis at mail.msen.com> 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?


>> Any strong objections?
> -- 
> Best regards,
> Igor Stasenko AKA sig.

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