Control.Combinators? Such general beasts as mapFst, mapSnd and >< from Data.Graph.Inductive.Query.Monad could go in there, as could other pair handling combinators like (f <&> g) x = (f x, g x)
Pair handling combinators could go into Data.Tuple. I append what I currently have. (This is a typical instance of the kind of module where the code is (at least an essential part of) the documentation. Can Haddock be told to include the code in the documentation? ) Wolfram --------------------------------------------------------------- \section{Tuple Utilities} \begin{code} module Data.Utils.Tuple where \end{code} \begin{code} swap (x,y) = (y,x) \end{code} \begin{code} pupd f g (x,y) = (f x, g y) mapPair f (x,y) = (f x, f y) mapTriple f (x,y,z) = (f x, f y, f z) pupd1 f (x,y) = (f x, y) pupd2 g (x,y) = (x, g y) {-# INLINE pupd #-} {-# INLINE pupd1 #-} {-# INLINE pupd2 #-} \end{code} \begin{code} keep1 f p@(x,y) = (x, f p) keep2 f p@(x,y) = (f p, y) \end{code}