Looping and collecting using monads

loopCollect.hs

loopCollect state0 xs func = fst $ runState (forM xs func) state0

-- result is ["hello", " ", "world"]
eg = loopCollect  "hello world" [5, 1, 5]
     (\i -> do
         str <- get
         let (h, t) = splitAt i str
         put t
         return h)