Python bytecode compatibility between interpreter versions

[Terry Reedy]

"Ronald Oussoren" <oussoren at cistron.nl> wrote in message
news:DD2E4369-7BE3-11D8-8375-0003931CFE24 at cistron.nl...
> >> In practice though, there is really just one implementation of Python
> >> (with the standard libraries... excluding Jython)

People who make their living with Jython would find the exclusion puzzling
;-)

> That's *two* implementations of Python: CPython and Jython, one of
> which uses pyc files. You're conveniently ignoring the primary example
> of a Python interpreter that does not use pyc files.

There are actually two more:

 3) Viper (now dead, I believe), which translated Python (+ 'enhancements')
to, I believe, with some fuzzyness, OCaml.

4) PyPy (as yet only partial, I believe), which, if funded for development
and spectacularly successful, could become the reference implementation
(but that is at best years away).

Nonetheless, CPython is now the main, reference implementation.  2.x.y .pyc
files are cross-platform portable.  I believe the same is also true
regardless of the '.y' part.  Reading PyDev, I have seen no evidence that
the planned 2.4 will be very much different.

Terry J. Reedy