[squeak-dev] Object>>is:

David T. Lewis lewis at mail.msen.com
Mon Feb 14 00:10:22 UTC 2011

On Mon, Feb 14, 2011 at 12:23:34AM +0100, Levente Uzonyi wrote:
> On Thu, 10 Feb 2011, David T. Lewis 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.
> >
> >Any strong objections?
> I agree with St?phane and Colin, we shouldn't add this method. I think 
> adding Object >> #is: alone won't help you much anyway.
> IMHO the following alternative solutions are better for integrating 
> SimpleMorphic, especially the first one:
> 1) use #is* instead of #is: *. This should work since there are only 26 
> implementors of #is: in Cuis. Almost all of them behave this way. The 
> only exception is #ShoutEnabled, but Cuis has a different Shout 
> implementation than Squeak, so you'll have to use the Squeak counterpart 
> of that anyway.
> 2) add the #is: methods as extension methods, maybe in a separate 
> compatibility package

Agreed, and thank you for the analysis and critique. My original
question was whether is it acceptable to add the default implementation
of Object>>is: into trunk as a means of providing support for external
packages that may have chosen to use it. Several people have strongly
objected, so I will not add it to trunk.

As you suggest, adding #is: as an extension method is perfectly acceptable.


p.s. There is currently a similar debate under way on the Pharo list
concerning #caseOf: and #caseOf:otherwise:. It appears that these two
methods have been living quiet and and productive lives for many years
within the community, albeit largely unnoticed by their neighbors.
Recently however, they have been exposed as idiologically impure,
and there is now an angry mob at the gates of the palace demanding
extermination of these impostors to object-oriented correctness. A
couple of people have vainly attempted to calm the public outrage by
defending the utility and harmless demeanor of these methods, but
they in turn are seen as apologists for the guilty, evidence perhaps
of a broader conspiracy. This is not a story that is likely to end
well, although I recommend it as an entertaining read for those with
a sense of humor. The tale begins here:



More information about the Squeak-dev mailing list