[Haskell-cafe] Re: Numeric type classes

Aaron Denney wnoise at ofb.net
Wed Sep 20 04:17:03 EDT 2006

On 2006-09-12, Jacques Carette <carette at mcmaster.ca> wrote:
> First, as already pointed out in
> http://www.haskell.org/pipermail/haskell-cafe/2006-April/015404.html
> there is a lot of relevant previous work in this area.

I'm afraid I don't see the relevance.

> This is very easy to do in 'raw' category theory, as concepts are not 
> _nominal_, so a functor from one type to another can explicitly do a 
> renaming if necessary.

Computer programming is of course extremely nominal to provide
abstraction and seperation of concerns.  Yes, anonymous functions are
handy, but I could give them up if I had named local functions.
Yes, you can even go to unlambda and only use combinators.  Practically
we find names extremely useful.

> Various algebraic specification languages have 
> thus adopted this too, so that you are not forced to give unique names 
> to all your concepts, you can in fact give them meaningful names 'in 
> context', and use a remapping when you want to say that you obey a 
> particular interface.

This sounds neat, but I'd be worried about how cumbersome it was in

> This is an old conversation, see
> http://www.haskell.org/pipermail/haskell/2005-October/016621.html
> for example.

Thanks.  The ML interface paper looks quite interesting.  Are you aware
of any implementations?

Aaron Denney

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