So, Perl wise, I've made a start on the thunking layer. It now seems to work okay - in the end I did it by polluting the error classes with extra methods. It's all a bit "run it and see if I get the right errors" atm. What I have at the moment in theory is the one I build to throw away (but we all know how often we end up keeping those.)
My next step is to beef up the test suite - the whole things runs out of an Apache::Test environment - so I can check that you can catch all the errors in the right place.
I've also been cargo culting like crazy with SubEthaFari which is a little mac xcode project that you build and shove in the right place in your ~/Library and through some crazy method swizzling (Object-C symbol replacing) it causes Safari to open it's source in SubEthaEdit rather than it's own source code viewer. This would be great, apart from two things. One, I can't use SubEthaEdit at work without either breaching the license terms or paying for it. Secondly, it's not emacs or vi.
So I followed the advice of others and did the two line change that made it work with the carbonised Emacs.app.
