OverloadedRecordFields status update

Adam Gundry adam.gundry at strath.ac.uk
Mon Sep 9 16:01:45 UTC 2013

On 09/09/13 16:53, Gabor Greif wrote:
> On 9/9/13, Adam Gundry <adam.gundry at strath.ac.uk> wrote:
>> On 06/09/13 17:45, Gabor Greif wrote:
>>> On 9/5/13, Adam Gundry <adam.gundry at strath.ac.uk> wrote:
>>>> 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.)



> ...

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