[antlr-interest] Preserving comments

[Martin Probst]

Hi,

> Unfortunately the actions must be context sensitive.
>
> What's the best way to tackle this practically?

It's possible to change the TokenStream implementation to link comment  
tokens to either the previous or the next token, whatever suits you  
best. For that, you'll also need a custom token class. You can then  
after parsing walk the AST with a plain old Java program, and do  
whatever you need to do.

I've used this technique in my ANTLR parser/pretty printer, see here:
http://code.google.com/p/xqpretty/source/browse/trunk/src/java/com/martinprobst/xqpretty/LazyTokenStream.java

and the 'setHiddenPredecessor' in XQToken.java.

Regards,
Martin