Playing with Haskell monads and do notation

DoNotation.hs

module DoNotation where

-- without do notation

-- applying only >>=
monadChainSuccess1 = Just "hello"     >>= \xs -> 
                     Just (xs ++ " ") >>= \ys ->
                     Just (ys ++ "world")

-- applying >>= and >>
monadChainSuccess2 = Just "hello" >> 
                     Just " "     >>= \ys ->
                     Just (ys ++ "world")

-- applying only >>=
monadChainFailure1 = Just "hello" >>= \xs ->
                     Nothing      >>= \ys ->
                     Just (ys ++ "world")

-- applying >>= and >>
monadChainFailure2 = Just "hello" >> 
                     Nothing      >>= \ys ->
                     Just (ys ++ "world")

-- with do notation

-- applying only >>=
doMonadChainSuccess1 = do hello <- Just "hello"
                          space <- Just " "
                          world <- Just "world"
                          Just (hello ++ space ++ world)

-- applying >>= and >>
doMonadChainSuccess2 = do hello <- Just "hello"
                          Just " "
                          world <- Just "world"
                          Just (hello ++ world)

-- applying only >>=
doMonadChainFailure1 = do hello <- Just "hello"
                          space <- Nothing
                          world <- Just "world"
                          Just (hello ++ space ++ world)

-- applying >>= and >>
doMonadChainFailure2 = do hello <- Just "hello"
                          Nothing
                          world <- Just "world"
                          Just (hello ++ world)

-- load on ghci and play with it ;)