Just curious, how does the Python 3 version get built without going through 2to3?

The idea is to target the common subset of Py 2.6+ and Python 3.x, if necessary with six.

That may have to be necessary, as the codebase is currently incompatible with Python 3: there's uses of intern in the language module:

https://gitlab.tiker.net/inducer/leap/blob/master/leap/vm/language.py#L103

Started that process in 122efa60.

My secret plan was to let Jenkins yell at us until Py3 works right, because my day-to-day working environment is still Py2.