Data commit

Task/First-class-functions/Haskell/first-class-functions.hs

@@ -0,0 +1,18 @@
+cube :: Floating a => a -> a
+cube x = x ** 3.0
+
+croot :: Floating a => a -> a
+croot x = x ** (1/3)
+
+-- compose already exists in Haskell as the `.` operator
+-- compose :: (a -> b) -> (b -> c) -> a -> c
+-- compose f g = \x -> g (f x)
+
+funclist :: Floating a => [a -> a]
+funclist = [sin,  cos,  cube ]
+
+invlist :: Floating a => [a -> a]
+invlist  = [asin, acos, croot]
+
+main :: IO ()
+main = print $ zipWith (\f i -> f . i $ 0.5) funclist invlist