Ulf Norell wrote:
I'm not sure what you're asking...
Me neither probably.
, but it's possible to get
my_read :: .. => Expr -> Term a
Previously given code:
-- Give a GADT for representation types data R a where Rint :: R Int Rbool :: R Bool Rpair :: R a -> R b -> R (a,b)
Yeah, I especially liked Joost Visser's version which is pretty slick. I was just wondering if it was possible to accomplish the same task in a different way, using type classes instead of GADTs, which would seem to work in a more top-downish fashion, as opposed to bottom-upish. But I'm not an expert enough with type systems to know if the... Ambiguous type variable `b' in the constraint: `MyRead b' arising from use of `my_read' at gadt_wobbly.hs:65:28-36 Probable fix: add a type signature that fixes these type variable(s) ...problem was fixable by adding a type signature or grafting on some additional type machinery. Thanks, Greg Buchholz