[Haskell-cafe] Hunting for ghci manual input vs. file input differences again
monkleyon at gmail.com
Fri May 5 11:30:34 UTC 2017
> You can use a `Proxy` argument to explicitly signal to GHC what type
> it should be, or TypeApplications, but I don't think either of those
> will help with implementing this.
I guess you're right. It seems my examples where only working because
somewhere along the line types where defaulted to () – throwing away any
information I did have. I suppose what I would actually need for the
elusive cast is something like a (forall a . c a :=> d a). I found some
interesting bits in Data.Constraint.Forall to pursue in that direction,
but I'm far from understanding how to use them.
Anyway, thanks for the help.
More information about the Haskell-Cafe