Just a quick note since I realise I haven't been too good at writing updates of late...
I'm currently working on a complete revamp of the AST, lexer and parser to allow for exact source info to be kept in the tree, which in turn will allow exact printing of the code as it was read. In the process I've included support for annotated AST trees (and the source info makes use of such labels). The problem with this is that it's a huge amount of work to get it all to a state where I can start testing it. I'm currently bashing away on the parser, which is by far the most difficult component to update, being happy-based and all.
I should add that the "old" simpler AST will still be there, the new complex AST with annotations will live in a different module, so this should all be backwards compatible. There will only be one parser though, which parses to the complex version, and then a simple translation function from annotated to simple. But the stuff exported from the parser will also still be backwards compatible, so stay your pitchforks and torches! :)