Re: Extending the do-notation

import Monad ... do y <- liftM unzip m1

Thanks. I'm constantly amazed by the number of tricks one has to know before he can write concise code using the do-notation (among other things, I used to write "x <- return $ m" instead of "let x = m"). Is there a paper demonstrating the most common coding styles for do-notation ? Another question concerning the do-notation: I noticed that most parts of ghc do not use it. Is it because the code was written before the notation was available, because the do-notation is too weak to express these parts, or for another fundamental reason ?