Pronounify.hs

import Data.String.Utils (replace)
import Data.Char (isUpper, toUpper)
import System.Environment (getArgs)

main :: IO ()
main = do 
  strings <- getArgs
  mapM_ (putStrLn . pronounify) strings

capitalise :: String -> String
capitalise (x:xs) = (toUpper $ x) : xs
capitalise "" = ""

isCapitalised :: String -> Bool
isCapitalised (x:_) = isUpper x
isCapitalised "" = False

forEachPronoun :: String -> String -> [String]
forEachPronoun x y = 
  let 
    orify a b = a ++ " or " ++ b
    commaify a b = a ++ ", " ++ b
    orifiedPronouns = [orify x y, orify y x]
    commaedPronouns = [commaify x y, commaify y x]
    combinedPronouns = orifiedPronouns ++ commaedPronouns
  in 
    combinedPronouns ++ map capitalise combinedPronouns

pronouns = 
  map (\((s, h), t) -> (forEachPronoun s h, t))
  [ (("she", "he"), "they")
  , (("her", "him"), "them")
  , (("her", "his"), "their")
  , (("hers", "his"), "theirs")
  , (("herself", "himself"), "themself")
  ]

pronounify :: String -> String
pronounify s = 
  let
    replacementF r s p
      | isCapitalised p = replace p (capitalise r) s
      | otherwise = replace p r s
    replacePronoun (ps, r) s = foldl (replacementF r) s ps
  in
    foldl (flip replacePronoun) s pronouns