[Python-Dev] VM and Language summit info for those not at Pycon (and those that are!)

["Martin v. Löwis"]

Am 21.03.2011 11:58, schrieb Stefan Behnel:
> [long post ahead, again]
> 
> Guido van Rossum, 21.03.2011 03:46:
>> Thanks for the clarifications. I now have a much better understanding
>> of what Cython is. But I'm not sold. For one, your attitude about
>> strict language compatibility worries me when it comes to the stdlib.
> 
> Not sure what you mean exactly. Given our large user base, we do worry a
> lot about things like backwards compatibility, for example.
> 
> If you are referring to compatibility with Python, I don't think anyone
> in the project really targets Cython as a a drop-in replacement for a
> Python runtime. We aim to compile Python code, yes, and there's a
> hand-wavy idea in the back of our head that we may want a plain Python
> compatibility mode at some point that will disable several important
> optimisations.

I think that's the attitude Guido worries about: if you don't have the
desire to provide 100% Python compatibility under all circumstances
(i.e. including if someone passes parameters of "incorrect" types),
then there is very little chance that we would replace a Python module
with a Cython-compiled one.

The only exception would be cases where the Python semantics is murky
(e.g. where Jython or so actually behaves differently for the same
 Python code, and still claims language conformance). E.g. the exact
message on a TypeError might change when compiling with Cython,
but the cases in which you get a TypeError must not change.

Regards,
Martin