tasks a-s

Task/Rock-paper-scissors/Haskell/rock-paper-scissors.hs

@@ -0,0 +1,36 @@
+import System.Random
+
+data Choice = Rock | Paper | Scissors
+ deriving (Show, Eq)
+
+
+beats Paper Rock = True
+beats Scissors Paper = True
+beats Rock Scissors = True
+beats _ _ = False
+
+genrps (r,p,s) = fmap rps rand
+  where rps x | x <= s    = Rock
+              | x <= s+r  = Paper
+              | otherwise = Scissors
+        rand = randomRIO (1,r+p+s) :: IO Int
+
+getrps = fmap rps getLine
+  where rps "scissors" = Scissors
+        rps "rock" = Rock
+        rps "paper" = Paper
+        rps _ = error "invalid input"
+
+game (r,p,s) = do putStrLn "rock, paper or scissors?"
+                  h <- getrps
+                  c <- genrps (r,p,s)
+                  putStrLn ("Player: " ++ show h ++ " Computer: " ++ show c)
+                  putStrLn (if beats h c then "player wins\n"
+                           else if beats c h then "player loses\n"
+                           else "draw\n")
+                  let rr = if h == Rock then r+1 else r
+                      pp = if h == Paper then p+1 else p
+                      ss = if h == Scissors then s+1 else s
+                  game (rr,pp,ss)
+
+main = game (1,1,1)