[Haskell-cafe] Re: Re: type class question

Jules Bean jules at jellybean.co.uk
Fri Dec 7 07:43:25 EST 2007

Peter Padawitz wrote:
> Functional dependencies don't work in my case. Actually, I don't see why 
> they should.

Ah well, it's cruel to say that without explaining to us why!

I'm not sure why a complete cyclic dep a -> b -> c -> d -> a isn't what 
you want.

> What seems to be needed here is a type class construct with a kind of 
> record parameter so that instance conflicts cannot occur.

I'm not entirely sure what you intend to mean by this, but if you mean 
what I guess you mean:

class Java (a,b,c,d) where ....

then I think that would appear to be the same thing as a complete cyclic 
fundep to me...


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