Is there an IDE out there that does structural syntax highlighting?

Question

Somewhat inspired by this question about a graphical programming environment. I don\'t think that C++ or C# are really conducive to this type of environment, but perhaps there\

Answer 1

A nice idea. Personally, I really don't like folding editors, but this would be quite tolerable - you'd want to be able to toggle it on/off easily though. Perhaps someone has already done this for the hyper-programmable editors like vim and emacs?