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Jeff,
Thanks, I will read it tonite when I get home. Without having read it, 
though, I can say that I still think of things as Categories in 
prototype-based languages. For instance, in Io, a create a 'class' with:

Dog = Object clone
Dog speak := method(write("bark"))

And then I create individual dogs with:

fido = Dog clone
spot = Dog clone

spot speak
fido speak

My point is that I still use the objects as if there were categories and 
classes of things (eg, you will still find a Button 'class') but that there 
are no differences between classes and instances as far as the language is 
concerned. But I am sure the author of the paper means something more 
profound.

Thanks again,
Jared Nuzzolillo


On 8/16/05, Brian Mitchell <binary42 / gmail.com> wrote:
> 
> On 8/16/05, Jeffrey Moss <jeff / opendbms.com> wrote:
> > > ...but I still feel that prototype-based languages have a certain
> > > conceptual elegance that is lacking in class-based alternatives.
> >
> > It's interesting the part western philosophy played in language design, 
> I
> > tend to agree with you about the conceptual nature of class vs prototype
> > inheritance, but class based inheritance is easier for me to use, easier 
> to
> > lay out in my mind.
> >
> > Here's an interesting read on the subject:
> > http://www.helsinki.fi/~jppesone/papers/kandi.html
> >
> > Summary:
> > From an ontological point of view the prototype-based languages win. 
> There
> > is little evidence of a strange platonic realm of categories, but
> > class-based languages don't necessarily have to be realist in their
> > ontology - a language can include universals and "Santa Claus" without
> > committing to realism (von Wrigth 1972, 198). Unless the prototype-based
> > languages include some notion of categories they lack something
> > psychologically very important: the capacity of categorization.
> >
> > -Jeff
> 
> Very interesting. Thanks for the link. This is all ironic right now as
> I am currently working on implementing a complete Ruby environment
> inside/using Io. It has been interesting on how easy it was to lay the
> class based design of Ruby over the prototype based Io. I am not quite
> done solidifying the final translation between the two but when I get
> further I will throw the code up for consumption.
> 
> Sometimes all we need is an initial pattern to help prime the mind.
> Then we can go on to clone or copy that pattern into classes or
> prototypes.
> 
> Brian.
> 
>

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