[Haskell-cafe] Re: Type classes and type equality

Neil Mitchell ndmitchell at gmail.com
Tue Apr 17 06:40:19 EDT 2007


Hi Oleg,

> > I'm looking for a type class which checks whether two types are the
> > same or not.
>
> For the full discussion of various solutions, please see Section 9 and
> Appendix D of the HList paper:
>         http://homepages.cwi.nl/~ralf/HList/paper.pdf

Thanks for pointing that out. As far as I can see, this requires a new
instance declaration for every type? In this sense, it would require
as many Typeable declarations, but have the downside that it isn't
build into any compiler.

I was really hoping for something that requires less work on behalf of the user.

Thanks

Neil


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