You can use the fun (.).(.) operator :D
sumProducts :: Num a => [a] -> [a] -> a
sumProducts = ((.).(.)) sum (zipWith (*))
In all seriousness though, points-free isn't always the most readable way to go.
On Sun, Jun 5, 2011 at 11:09 PM, Alexander Shendi
Hi folks,
I am working my way through "Learn You a Haskell for Great Good" and have reached page 84, where the book recommends that you define your functions in a "points-free style", using the "." and "$" operators.
Now I have:
sumProducts' :: Num a => [a] -> [a] -> a sumProducts' x y = sum (zipWith (*) x y)
I would like to eliminate the "x" and the "y" in the definition, but all I have managed to contrive is:
sumProducts :: Num a => [a] -> [a] -> a sumProducts x = sum . zipWith (*) x
How do I proceed from here? Any advice is welcome :)
Many thanks in advance,
/Alexander
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