You might want to look at the arrow type class and the instance for (->).
Ben On 28 May 2013 09:56, "Dominique Devriese" < dominique.devri...@cs.kuleuven.be> wrote: > Hi all, > > I often find myself needing the following definitions: > > mapPair :: (a -> b) -> (c -> d) -> (a,c) -> (b,d) > mapPair f g (x,y) = (f x, g y) > > mapFst :: (a -> b) -> (a,c) -> (b,c) > mapFst f = mapPair f id > > mapSnd :: (b -> c) -> (a,b) -> (a,c) > mapSnd = mapPair id > > But they seem missing from the prelude and Hoogle or Hayoo only turn > up versions of them in packages like scion or fgl. Has anyone else > felt the need for these functions? Am I missing some generalisation > of them perhaps? > > Regards, > Dominique > > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe >
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