DMD AST Docs/Reference or Dumper?

[bitwise via Digitalmars-d]

I'm trying to add some compile-time function generation to dmd, 
but wasn't sure exactly how to click all the little legos 
together.

Is there any documentation or reference for the DMD AST? Or maybe 
some examples somewhere of what an AST may look like for a given 
function?

As a last resort, I was about to start converting the 
ToJsonVisitor to a ToAstDumpVisitor, but as you may have guessed, 
I am not particularly excited about this venture. Does source 
code exist anywhere for this already?

Thanks