[Haskell-cafe] ANN: exists-0.1

[Mikhail Vorozhtsov]

On 02/07/2012 04:05 PM, Gábor Lehel wrote:
> On Tue, Feb 7, 2012 at 7:23 AM, Mikhail Vorozhtsov
> <mikhail.vorozhtsov at gmail.com>  wrote:
>> Even better, you can write
>>
>> type ExistentialWith c e = (Existential e, c ~ ConstraintOf e)
>>
>> instead of
>>
>> class    (Existential e, c ~ ConstraintOf e) =>  ExistentialWith c e
>> instance (Existential e, c ~ ConstraintOf e) =>  ExistentialWith c e
>>
>> and drop UndecidableInstances.
>
> I actually mentioned this in the preceding point of the [snip]. The
> problem is that it's not even better because you can't partially apply
> it.
Ah, sorry, I got sloppy. Have you encountered situations where partial 
application of such "constraint aliases" becomes a problem?