[Haskell-cafe] Polymorphic addition function with variable number of arguments?

Johannes Waldmann waldmann at imn.htwk-leipzig.de
Tue Mar 13 20:30:50 CET 2012

> Can someone tell me why this is not working 

that "someone" is actually ghci:

Prelude> instance (Num a, Add a b) => Add (a -> b) where add x y = add (x + y)

    Expecting one more argument to `Add (a -> b)'
    In the instance declaration for `Add (a -> b)'

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