Hello,

I have no strong feelings about what words we use, but I wanted to point out that while we are thinking of names, we may want to consider 3 (and not just 2).  Currently we have:
  * OVERLAPPING:   This instances may overlap existing instances
  * OVERLAPPABLE: This instance may be overlapped by existing instances
  * OVERLAPS:  This instance is both OVERLAPPING and OVERLAPPABLE

Of course, the 3rd one (OVERLAPS) could be replaced by a comma separated list of the first two, but I could not see how to make this work easily with GHC's pragmas.  It would not be hard to simply allow 2 pragmas after the `instance` keyword, but both of those seem rather long.

Either way, I'll keep an eye on the discussion, and would be happy to change the names if a consesus is reached.

-Iavor













On Tue, Jul 29, 2014 at 9:57 AM, David Thomas <davidleothomas@gmail.com> wrote:
Honestly, I think "OVERLAPS" and "OVERLAPPED" are perfectly clear.

On Tue, Jul 29, 2014 at 9:52 AM, David Feuer <david.feuer@gmail.com> wrote:
> CAN-OVERLAP and CAN-BE-OVERLAPPED are nice and clear. A little long, perhaps.
>
> On Tue, Jul 29, 2014 at 12:29 PM, Simon Peyton Jones
> <simonpj@microsoft.com> wrote:
>> CAN_OVERLAP and CAN_BE_OVERLAPPED?
>>
>>
>>
>> (instead of OVERLAPPING and OVERLAPPABLE)
>>
>>
>>
>> Or CAN-OVERLAP, CAN-BE-OVERLAPPED
>>
>>
>>
>> That’s ok with me if that’s what you all want!
>>
>>
>>
>> Simon
>>
>>
>>
>> From: Glasgow-haskell-users
>> [mailto:glasgow-haskell-users-bounces@haskell.org] On Behalf Of Krzysztof
>> Skrzetnicki
>> Sent: 29 July 2014 16:56
>> To: Brandon Allbery
>> Cc: Simon Peyton Jones; Andreas Abel; GHC users; Haskell Libraries
>> (libraries@haskell.org); ghc-devs
>>
>>
>> Subject: Re: Overlapping and incoherent instances
>>
>>
>>
>> How about CAN_OVERLAP?
>>
>> --
>> Krzysztof
>>
>> 29-07-2014 15:40, "Brandon Allbery" <allbery.b@gmail.com> napisał(a):
>>
>> On Tue, Jul 29, 2014 at 8:33 AM, Andreas Abel <andreas.abel@ifi.lmu.de>
>> wrote:
>>
>> +1. I like Niklas' syntax better.  Also OVERLAPPABLE is a horrible word,
>> OVERLAPPING sound less formidable (even though it might be slightly less
>> accurrate).
>>
>>
>>
>> We already get "overlap ok" in instance-related type errors, so OVERLAP_OK
>> wouldn't be particularly alien even if it doesn't quite fit in with existing
>> pragmas.
>>
>>
>>
>> --
>>
>> brandon s allbery kf8nh                               sine nomine associates
>>
>> allbery.b@gmail.com                                  ballbery@sinenomine.net
>>
>> unix, openafs, kerberos, infrastructure, xmonad        http://sinenomine.net
>>
>>
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