Merge pull request #3225 from stuart-little/stuart-little_095_haskell

1st commit on 095_haskell

2 files changed, 42 insertions, 0 deletions

diff --git a/challenge-095/stuart-little/haskell/ch-1.hs b/challenge-095/stuart-little/haskell/ch-1.hs
new file mode 100755
index 0000000000..167b8b55c0
--- /dev/null
+++ b/challenge-095/stuart-little/haskell/ch-1.hs
@@ -0,0 +1,10 @@
+#!/usr/bin/env runghc
+
+-- run <script> <number>
+
+import System.Environment (getArgs,)
+import Math.TreeFun.Tree (boolToInt,)
+
+main = do
+  (nr:_) <- getArgs
+  putStrLn $ show $ boolToInt (nr == reverse nr)
diff --git a/challenge-095/stuart-little/haskell/ch-2.hs b/challenge-095/stuart-little/haskell/ch-2.hs
new file mode 100755
index 0000000000..3f83159642
--- /dev/null
+++ b/challenge-095/stuart-little/haskell/ch-2.hs
@@ -0,0 +1,32 @@
+#!/usr/bin/env runghc
+
+-- run <script>
+
+import System.Environment (getArgs,)
+import Control.Monad (liftM,)
+import Data.Maybe (fromMaybe,fromJust,)
+import Data.Stack (Stack,stackIsEmpty,stackNew,stackPop,stackPush,stackPeek,)
+
+maybeMin :: Ord a => Maybe a -> Maybe a -> Maybe a
+maybeMin (Just x) (Just y) = Just (min x y)
+maybeMin (Just x) _ = Just x
+maybeMin _ (Just x) = Just x
+maybeMin _ _ = Nothing
+
+stackMinimum :: Ord a => Stack a -> Maybe a
+stackMinimum stack
+  |stackIsEmpty stack = Nothing
+  |otherwise = maybeMin (stackMinimum rest) (Just popped) where
+     (rest,popped) = fromJust $ stackPop stack
+     
+main = do  
+  let
+    stack :: Stack Int
+    stack = foldl stackPush (stackNew) [0,-1,3,10,4]
+  putStrLn $ "Initial stack: " ++ (show stack)
+  let (rest,popped) = fromJust $ stackPop stack
+  putStrLn $ "Popped: " ++ (show popped)
+  putStrLn $ "New stack: " ++ (show rest)
+  putStrLn $ "Peeking: " ++ (show $ fromJust $ stackPeek rest)
+  putStrLn $ "Current stack: " ++ (show rest)
+  putStrLn $ "Smallest value: " ++ (show $ fromJust $ stackMinimum rest)