[Haskell] Re: [Haskell-cafe] ANNOUNCE: Generic Haskell 1.80 (Emerald)

Pablo Nogueira pablo at babel.ls.fi.upm.es
Sat Apr 12 13:14:19 EDT 2008

On 12/04/2008, Thomas van Noort <thomas at cs.ru.nl> wrote:

> That's a good question. Unfortunately, only Haskell98 types are currently
>  supported by the Generic Haskell compiler.

I thought constrained types were Haskell 98, but now I'm in doubt...

>  But at first sight, implementing support for parametric types with class
>  constraints is not too hard. Class constraints of a parametric type need
>  to be propagated to its generated structure type.

Certainly, but there are a few difficulties for higher-kinded types.
An arguable solution: http://portal.acm.org/citation.cfm?id=1159868

The reason I mention this is because Scrap your Boilerplate supports
them whereas GH does not, and I'm not aware this has been taken into
account when comparing these two approaches in the work cited by Bulat
on this thread.

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