[Haskell-beginners] Loop

[amindfv at gmail.com]

What you really want is "replicateM_". But to answer your original question, you could do something like:

import Control.Monad.List
main = runListT $ do
  _ <- ListT $ pure [1,2,3,4]
  liftIO $ putStrLn "Test"

(replicateM_ is way better though)

Tom


El May 1, 2015, a las 10:23, Marcin Mrotek <marcin.jan.mrotek at gmail.com> escribió:

> It depends on what are you trying to achieve. The ListT monad
> transformer is an overkill for your example, as you don't use the
> "non-determinism" feature of ListT (code written using it can use
> whole lists of values as if it was one value with multiple "versions",
> any action can return any number of results, which are then combined
> together, perhaps without even calculating all of them if they're not
> needed); if you just want to sequence actions, it's enough to use
> mapM, mapM_, sequence, sequence_, and other functions from
> Control.Monad. But if you have something more complicated in mind, it
> might be worth taking a look at ListT and other transformers to see if
> they can be of any use to you.
> 
> Best regards,
> Marcin Mrotek
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