Re: [Haskell-cafe] Are there arithmetic composition of functions?

[Chris Smith]

On Mar 19, 2012 11:40 AM, "Ozgur Akgun" <ozgurak...@gmail.com> wrote:
> {-# LANGUAGE FlexibleInstances #-}
>
> instance Num a => Num (a -> a) where

You don't want (a -> a) there.  You want (b -> a).  There is nothing about
this that requires functions to come from a numeric type, much less the
same one.

-- 
Chris Smith

_______________________________________________
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe