OT: Less-restrictive alternative to XML and XML visualizers?

[BCS]

Reply to Nick,

> I'm working on a high-level-language processing tool as a pet project
> (at the moment it just parses grammars compiled with the GOLD tool),
> and (especially for debugging) I'd like to output the parse tree and
> eventually AST in a way that I can easily/visually inspect the
> resulting trees.

Our stuff would be a little weak on the rendering side (it's extensable enought 
to fix that but it would involve a little work)

Take a look at YAML if it looks like it might be intereting to you our stuff 
might as well. If you're intereted send my your email.