Re: OverloadedRecordFields status update

9 Sep 2013

      On 09/09/13 16:53, Gabor Greif wrote:
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On 9/9/13, Adam Gundry  wrote:
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On 06/09/13 17:45, Gabor Greif wrote:
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On 9/5/13, Adam Gundry  wrote:
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I have been working on a new extension, OverloadedRecordFields, and it
is now essentially feature-complete. Unfortunately, I doubt it will make
it into 7.8, as the changes are quite extensive, but I hope to get it in
HEAD soon thereafter.
That would be great, it appears to be a great example of
-XConstraintKinds, too!
It relies quite heavily on type-level strings (-XDataKinds), if that's
what you mean?
No, I mean ConstraintKinds, I assume all the Has* constraints have
kind 'Constraint' ?
(I strongly assume so).
Ah, I see your point. Yes, the kind of `Has` is

    * -> Symbol -> * -> Constraint

although it is actually implemented as a typeclass in the base library,
so in this respect it's not particularly special. (Instances of the
typeclass are automatically generated and cannot be given in the normal
way, however.)

Cheers,

Adam
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