"Have the data flow in one direction" is a good rule of thumb in writing clear Haskell code. That said, your conversion away from $ changes the meaning here (i

"Have the data flow in one direction" is a good rule of thumb in writing clear Haskell code. That said, your conversion away from $ changes the meaning here (in a way that doesn't typecheck, I think - remember that regular function application binds tightest whereas dollar binds loosest) and you still don't achieve your goal. Instead, maybe return . fromMaybe defaultPort $ readMaybe =<< maybeEnvPort or even return $ fromMaybe defaultPort $ readMaybe =<< maybeEnvPort If you still don't like the dollar signs, we can parenthesize instead in two correct ways, although I don't find them more readable: (return . fromMaybe defaultPort) (readMaybe =<< maybeEnvPort) return (fromMaybe defaultPort (readMaybe =<< maybeEnvPort))