On 28/09/2017 12:25, Baa wrote:
Hello, Sylvain.
Your solution assumes that I need to pass `@_ @AsTitle` anywhere where I call `repr`? So, instead of `repr n::AsTitle` or `repr n::Something AsTitle` (depends on implementation) I'll write `repr @_ @AsTitle n`, right? Yes.
You could also avoid all this ambiguity/type application stuff with: data AsTitle = AsTitle class Repr a b where repr :: a -> b -> Repr b instance Repr Int AsTitle where repr n _ = ... ... print (repr n AsTitle) (Repr b can be an associated type if you want to support different representations)
You only add a constraint as follows: repr n :: forall b. (Repr b ~ Repr AsTitle, ReprC Int b) => Repr b Yes... So, `b` is unbound/free type param. But I can bind it with func. deps, yes?
How? If you you bind it with a functional dependency on "a", you can only have a single "b" for each "a". Sylvain