Excellent bikeshedding opportunity! Frontend syntax for pattern synonym types

Dr. ERDI Gergo gergo at erdi.hu
Sun Dec 22 15:19:18 UTC 2013

On Sun, 22 Dec 2013, Gábor Lehel wrote:

> Other than being
>  A. displayed in the Haddocks
> will this syntax also, now or at any later point, be
>  B. explicitly written by the programmer alongside the definition of the pattern, or
>  C. used as a type argument for other types?

A and B.

> If it's only A and B, perhaps abominations like these could be considered:
>     -- implicit foralls
>     pattern Show t => P t :: (Num t, Eq b) => b -> T t
>     -- explicit foralls
>     pattern forall t. Show t => P t :: forall b. (Num t, Eq b) => b -> T t

I'm not 100% sure what that 't' in 'P t' is supposed to be in your 
example. 'P' is not like a type constructor at all; it's a lot more like a 
data constructor.


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