Haskellでループのbreak

継続モナド使おう。

http://hackage.haskell.org/packages/archive/mtl/2.1.2/doc/html/Control-Monad-Cont.html

import Control.Monad
import Control.Monad.Cont

main :: IO ()
main = do
  (`runContT` const (return ())) $ do
    callCC $ \k -> do
      forM_ [1..10] $ \i -> do
        when (i > 5) $ k ()
        liftIO $ print i