I am surprised (and to some extent disappointed) that he did not know about trampolines, as it's common knowledge among language implementors (e.g. it's used everywhere to implement proper tail recursion for FFI calls).
Somehow I though that being a language creator (or working on a compiler for a decade) implies unimaginable amount of knowledge...
Doing a lot trumps knowing a lot, even when you make mistakes. It's amazing what GVR has accomplishled despite (apparently) being ignorant of things other language designers know about.
I think GvR's special expertise is more in the 'user-interface' of programming languages than in their implementation. The whole point of Python, really, is to put the former before the latter; which is exemplified in GvR's 'readable-stack-traces before fancy-features-in-the-implementation' reasoning on the present point.
Even if you’re designing for professional programmers, in the end your programming language is basically a user-interface design. You will get much better results regardless of what you’re trying to do if you think of it as a user-interface design. Alan Kay http://queue.acm.org/detail.cfm?id=1039523
I was just starting some state-machine code in Clojure last night, thought about how to best do it functionally (recur doesn't let you cross function boundaries), and said out loud "I'll use a trampoline!"
If that happens again, I can tell the person I confused not to feel badly, because even Guido van Rossum didn't know about trampolines until recently.
