Re: [Haskell-cafe] SYB: extending a generic reader with a type class

Hi, I don't think you can do that, since `ext` relies on Typeable and Typeable only works for monomorphic types. Cheers, Pedro On Wed, Feb 2, 2011 at 20:31, Sugar Bzzz wrote:

Dear -cafe,

Is it possible to extend a generic reader (extR / ext1R from syb) with a type class?

For example, let

foo :: (Integral a) => SomeMonad a

I could write:

reader = ... `extR` (foo :: SomeMonad Int) `extR` (foo :: SomeMonad Integer)

However, that is tedious. Could I do something like

reader = ... `extR` foo

and have it apply to all instances of Integral?

I hope I am being clear.

Thank you.

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