Is the Visitor pattern really the best we've got for tree processing?
I'm processing tree data structures, possibly with embedded links (so they're actually DAGs), iteratively, with a different processing step each time. The code is very similar in spirit to writing an LLVM pass: http://llvm.org/docs/WritingAnLLVMPass.html
If you have any links to research or articles on coding idioms for tree processing, or other insight, I'd very much appreciate it. :)