Re: [Haskell-cafe] Phantoms

On Fri, 15 Aug 2008, Jules Bean wrote:

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?

Btw. was anything bad about the suggested Haskell98 solution?