Hi, you may use (f .) . g.
Wolfgang On Thursday, 2003-07-17, 02:27, CEST, Dr Mark H Phillips wrote: > Hi, > > Hopefully this is a simple question. I am wanting to know good ways > of using ".", the function composition operator, when dealing with > currying functions. > > Suppose I have the following functions defined: > > f :: Int -> Int > f x = x*x > > g :: Int -> Int -> Int > g a b = a + b > > If I wish to add 1 and 2 together and then square them I can do: > > f (g 1 2) = 9 > > but what if I wish to use function composition in the process? > > I can't do > > (f.g) 1 2 > > because the 2 doesn't get passed in till too late. > > I could do > > (f.(g 1)) 2 > > or even > > (f.(uncurry g)) (1,2) > > But what I really want is a function with signature Int -> Int -> Int. > The answer is probably: > > (curry (f.(uncurry g))) 1 2 > > but this seems awfully messy just to do f (g 1 2). > > And what if g were a function with three curried arguments? Then > uncurry and curry wouldn't apply. What then? > > Is there a better way? > > Thanks, > > Mark. _______________________________________________ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell
