Re: PolyKinds, Control.Category and GHC 7.6.1
I presume people are still interested in this. I actually just ran
into Category's non poly-kinded-ness the other day (while attempting
to make a Category instance for promoted pairs) and found this email
in my history.
Can we schedule this for 7.8.1? There's -plenty- of time, and the
addendum to Control.Category that Edward posted originally is pretty
much all that is needed. If that sounds OK, I can post a patch for
review or commit it directly to base.
On Tue, Aug 14, 2012 at 6:14 AM, Simon Peyton-Jones
| FWIW PolyKinds in 7.4 is rough, and I had experiences where enabling it | led to compile failures in downstream modules, so this wouldn't | necessarily have been painless. Hopefully with 7.6 it will be.
PolyKinds is not an advertised feature of 7.4, so you should absolutely not rely on it working in 7.4. But it IS an advertised feature for 7.6 and should work flawlessly. (If not, yell.)
Simon
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-- Regards, Austin - PGP: 4096R/0x91384671
Fine by me.. it's a library question at this point, so if the librarians are happy so am I
Simon
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| -----Original Message-----
| From: Austin Seipp [mailto:aseipp@pobox.com]
| Sent: 16 May 2013 17:00
| To: Simon Peyton-Jones
| Cc: Gábor Lehel; Edward Kmett; Ian Lynagh; Haskell Libraries; ghc-
| devs@haskell.org
| Subject: Re: PolyKinds, Control.Category and GHC 7.6.1
|
| I presume people are still interested in this. I actually just ran into
| Category's non poly-kinded-ness the other day (while attempting to make
| a Category instance for promoted pairs) and found this email in my
| history.
|
| Can we schedule this for 7.8.1? There's -plenty- of time, and the
| addendum to Control.Category that Edward posted originally is pretty
| much all that is needed. If that sounds OK, I can post a patch for
| review or commit it directly to base.
|
| On Tue, Aug 14, 2012 at 6:14 AM, Simon Peyton-Jones
|
Also, apologies for reviving a thread. I also did not include Edward's original message for better context. It is inline below. -------------------------- Would it be possible to add something like {-# LANGUAGE CPP #-} #if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ >= 704 {-# LANGUAGE PolyKinds #-} #endif to the top of Control.Category before the 7.6.1 final release? Control.Category.Category is pretty much the only type in base that directly benefits from PolyKinds without any code changes, but without enabling the extension there nobody can define categories for kinds other than *, and most interesting categories actually have more exotic kinds. I only noticed that it wasn't there in the release candidate just now. -Edward Kmett -------------------------- -- Regards, Austin - PGP: 4096R/0x91384671
participants (2)
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Simon Peyton-Jones