Raindrops.hs

module Raindrops
  ( convert
  )
where

import           Data.Semigroup                 ( (<>) )
import           Data.Maybe                     ( fromMaybe )

sounds :: [String]
sounds = ["Pling", "Plang", "Plong"]

convert :: Int -> String
convert n = fromMaybe (show n)
  $ foldr soundIfDivisible Nothing (zip sounds [3, 5 ..])
 where
  soundIfDivisible (s, x) acc | n `mod` x == 0 = Just s <> acc
                              | otherwise      = acc