fay-0.12.0.0: tests/basicFunctions.hs

import           Prelude

main = putStrLn (concat' ["Hello, ","World!"])

concat' = foldr' append []

foldr' f z []     = z
foldr' f z (x:xs) = f x (foldr f z xs)

append (x:xs) ys = x : append xs ys
append []     ys = ys