[squeak-dev] On class/metaclass coupling
siguctua at gmail.com
Tue Dec 8 14:12:22 UTC 2009
2009/12/8 Nicolas Cellier <nicolas.cellier.aka.nice at gmail.com>:
> 2009/12/8 Nicolas Cellier <nicolas.cellier.aka.nice at gmail.com>:
>> 2009/12/8 Ralph Johnson <johnson at cs.uiuc.edu>:
>>> If you haven't done this already, you should look up Actalk, which was
>>> a version of Smalltalk that let you have many classes with the same
>>> I never used Actalk, I just read the papers. It was an interesting
>>> and worthwhile experiment, but I wasn't convinced that the change was
>>> worthwhile. But perhaps we just need to figure out more to do with
>>> What you are saying is a little different. You are just complaining
>>> about hardcoding the assumption that each clas has a unique metaclass.
>>> All you are really asking is to get rid of the "thisClass" variable.
>>> I don't see any harm in that. I bet that "new" is rarely called more
>>> than once on any metaclass, and that one time is during the creation
>>> of the class/metaclass pair. The bigger issue is that when you
>>> evaluate and print the expression "Object class", what happens is that
>>> it computes the metaclass and then asks the metaclass to print itself,
>>> which it does by fetching the name of its sole instance and appending
>>> " class" to it. In other words, a metaclass does not have a name, but
>>> derives its name from the name of its sole instance. But this doesn't
>>> have to be fast, either. You could call allInstances to find out the
>>> instance and get its name. My guess is that it would hardly be
>> My own guess is that there would be a noticeable down speed in code
>> management tools (Monticello & al).
> Posted too fast...
> Beside, if it has several instances, then why insisting on giving a
> name related to a specific instance ?
i second that.
If problem is only about identifying metaclass by name, then
why not just add a 'name' ivar to metaclass, and let metaclass to
print itself with whatever name it desire?
Igor Stasenko AKA sig.
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