Trac: https://ghc.haskell.org/trac/ghc/ticket/10843 I would like the following to be valid Haskell code: main = when True do putStrLn "Hello!" Instead of requiring a dollar sign before the "do". This would parse as main = when True (do putStrLn "Hello!") Has this been tried before? It seems fairly simple -- is there some complexity I'm missing? I've always been confused as to why the parser requires `$` there, and I've heard a lot of others ask about this as well. Perhaps we could fix that? PS. Regardless of whether this goes anywhere, it was fun to learn how to hack on GHC. It was surprisingly easy; I wrote up my experience here http://rawgit.com/gibiansky/4c54f767bf21a6954b23/raw/67c62c5555f40c6fb67b124.... The GHC wiki is outstanding; pretty much every intro question about ghc development I had was answered on a fairly easy-to-find wiki age. (Except for some stuff related to generating documentation and docbook, but whatever.)