I don't recall exactly why they aren't in the struct itself, it may not 
have worked with some compiler on some platform.

It's not really a complete rewrite, the encoding path is largely the 
same and the tests haven't changed.

Anyway, there is no further work planned for simplejson. It's done 
except for the potential for bug fixes. The only enhancements were 
performance related and this is about as fast as it's going to get. The 
majority of this work was ready before Python 2.6 was released but it 
was frozen so I couldn't get this in.