Type checker plugins

Carter Schonwald carter.schonwald at gmail.com
Fri Oct 17 01:39:57 UTC 2014


mind you, i'm not sure what the ordering is specified to be :)

On Thu, Oct 16, 2014 at 9:24 PM, Carter Schonwald <
carter.schonwald at gmail.com> wrote:

> http://hackage.haskell.org/package/base-4.7.0.1/docs/GHC-TypeLits.html
>
> type family CmpSymbol m n :: Ordering
> <http://hackage.haskell.org/package/base-4.7.0.1/docs/Data-Ord.html#t:Ordering>
>
> On Thu, Oct 16, 2014 at 7:14 PM, Barney Hilken <b.hilken at ntlworld.com>
> wrote:
>
>> Ok, I hadn't realised that. Looking in the user's guide, I see <= and <=?
>> for Nat, but I couldn't find anything about Symbol. I must try them out!
>>
>>
>> > From: Carter Schonwald <carter.schonwald at gmail.com>
>> >
>> > the alphabetical ordering on Symbol is already exposed via TypeLits...
>> this would be some machinery to help maintain that ordering with less user
>> intervention?
>> >
>> > On Thu, Oct 16, 2014 at 6:59 PM, Barney Hilken <b.hilken at ntlworld.com>
>> wrote:
>> > I can think of a use for a non-equality constraint: an alphabetical
>> ordering on Symbol. This would allow experimental implementations of
>> extensible records (without shadowing) which keep the labels sorted.
>> >
>> > An order constraint on Nat might be useful, too.
>> >
>> > Barney.
>> >
>> > _______________________________________________
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>> >
>>
>
>
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