[Haskell-cafe] Injective type families for GHC - syntax proposals

Niklas Haas haskell at nand.wakku.to
Fri Sep 19 05:34:58 UTC 2014


On Fri, 19 Sep 2014 00:17:49 +0400, flicky frans <flickyfrans at gmail.com> wrote:
> Sorry.
> 
>    type family Plus a b = r :: Nat | r a -> b, r b -> a where

+1

Simple, intuitive and backwards compatible. I don't have to introduce a
variable if I don't want to, either.


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