Re: [Haskell-cafe] Phantoms

Malcolm Wallace wrote:

Andrew Coppin wrote:

...

...

instnace Show (Foo Int) ... instnace Show (Foo Double) ...

...WHY did I not think of this myself? o_O

Because it is not Haskell'98? It requires {-# LANGUAGE OverlappingInstances #-}

No it doesn't? It requires the much more semantically simple -XFlexibleInstances, as far as I know. Overlapping would only be needed if there was also a polymorphic instance on Foo a? Jules