Editing Foreach loop (section)

=== Haskell ===
[[Haskell]] allows looping over lists with [[Monad (functional programming)|monadic]] actions using <code>mapM_</code> and <code>forM_</code> (<code>mapM_</code> with its arguments flipped) from [http://hackage.haskell.org/package/base-4.6.0.1/docs/Control-Monad.html Control.Monad]:

{| class="wikitable"
! code !! prints
|-
|
<syntaxhighlight lang=Haskell>
mapM_ print [1..4]
</syntaxhighlight>
|
 1
 2
 3
 4
|-
|
<syntaxhighlight lang=Haskell>
forM_ "test" $ \char -> do 
    putChar char
    putChar char
</syntaxhighlight>
|
 tteesstt
|}

It's also possible to generalize those functions to work on applicative functors rather than monads and any data structure that is traversable using <code>traverse</code> (<code>for</code> with its arguments flipped) and <code>mapM</code> (<code>forM</code> with its arguments flipped) from [http://hackage.haskell.org/package/base-4.6.0.1/docs/Data-Traversable.html Data.Traversable].