A-M baby

Task/Loops-While/Haskell/loops-while-1.hs

@@ -0,0 +1,5 @@
+import Control.Monad (when)
+main = loop 1024
+  where loop n = when (n > 0)
+                      (do print n
+                          loop (n `div` 2))

Task/Loops-While/Haskell/loops-while-2.hs

@@ -0,0 +1,5 @@
+import Control.Monad (when)
+
+whileM :: (Monad m) => m Bool -> m a -> m ()
+whileM cond body = do c <- cond
+                      when c (body >> whileM cond body)

Task/Loops-While/Haskell/loops-while-3.hs

@@ -0,0 +1,9 @@
+import Data.IORef
+
+main :: IO ()
+main = do r <- newIORef 1024
+          whileM (do n <- readIORef r
+                     return (n > 0))
+                 (do n <- readIORef r
+                     print n
+                     modifyIORef r (`div` 2))