The items in your do-block must be in the same monad as you're operating in - in this example - the list monad: main = do x <- return $ do [ 1 ] [ 2 ] [ 3 ] print (x :: [Int]) Unfortunately, there is no accumulation of items. You can reason this out if you desugar the do-notation into binds: [ 1 ] >> [ 2 ] >> [ 3 ] [ 1 ] >>= (\x -> [ 2 ] >>= (\y -> [ 3 ])) and then examine the list Monad instance. You can achieve something similar to what you're looking for with the writer monad: import Control.Monad.Writer.Lazy main = do x <- return $ execWriter $ do tell [1] tell [2] tell [3] print (x :: [Int]) On Fri, Jan 23, 2015 at 3:04 PM, Cody Goodman <codygman.consulting@gmail.com

wrote:

List is a monad, does that mean i can create a list with do notation?

My intuition led me to believe this would work:

main = do x <- return $ do 1 2 3 print (x :: [Int])

However it didn't. Is this possible?

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