Indicate that Array monad is a nested for loop

Author: JordanMartinez

src/Control/Monad.purs

@@ -31,6 +31,17 @@ import Data.Unit (Unit)
 class (Applicative m, Bind m) <= Monad m
 
 instance monadFn :: Monad ((->) r)
+
+-- | The `Array` monad's "do notation" works like a nested for loop:
+-- | ```
+-- | foo :: Array Int
+-- | foo = do
+-- |   eachElementInArray1 <- [0, 1]
+-- |   eachElementInArray2 <- [1, 2]
+-- |   pure (eachElementInArray1 + eachElementInArray2)
+-- |
+-- | foo == [(0 + 1), (0 + 2), (1 + 1), (1 + 2)] == [1, 2, 2, 3]
+-- | ```
 instance monadArray :: Monad Array
 
 -- | `liftM1` provides a default implementation of `(<$>)` for any