The rationale and proposed semantics sections of PEP 3150 have been heavily modified based on the various discussions on the topic back in April. http://www.python.org/dev/peps/pep-3150/ (Note that the PEP is still officially Deferred - this entire idea still intrigues me, but I'm also still not convinced it's worth the additional language complexity). Cheers, Nick. -- Nick Coghlan | ncoghlan at gmail.com | Brisbane, Australia