FancyReplace.hs

module Codewars.Kata.FancyReplace where

import Data.Functor
import Data.List

getNumber :: Integer -> Either Integer  String
getNumber n | n `mod` 15 == 0 = Right "BOTH"
            | n `mod` 3  == 0 = Right "THREE"
            | n `mod` 5  == 0 = Right "FIVE"
            | otherwise       = Left n

getNumberRange :: Integer -> Integer -> [Either Integer String]
getNumberRange first last = getNumber <$> (reverse $ getRange first last [])
  where 
  getRange n m ns | n == m    = (n:ns)
                  | n < m     = getRange (n+1) m (n:ns)
                  | n > m     = getRange (n-1) m (n:ns)
                  | otherwise = ns