— Hangman example from chapter 10 of Programming in Haskell,
— , Cambridge University Press, 2016.
import System.IO
hangman :: IO ()
hangman = do putStrLn “Think of a word:”
word <- sgetLine
putStrLn "Try to guess it:"
play word
sgetLine :: IO String
sgetLine = do x <- getCh
if x == '\n' then
do putChar x
return []
else
do putChar '-'
xs <- sgetLine
return (x:xs)
getCh :: IO Char
getCh = do hSetEcho stdin False
x <- getChar
hSetEcho stdin True
return x
play :: String -> IO ()
play word = do putStr “? ”
guess <- getLine
if guess == word then
putStrLn "You got it!!"
else
do putStrLn (match word guess)
play word
match :: String -> String -> String
match xs ys = [if elem x ys then x else ‘-‘ | x <- xs]