[Cython] [Python-Dev] Using Cython for standard library?

[Stefan Behnel]

Hi,

Robert Bradshaw wrote:
> I think the most immediate official milestone is being able to  
> compile 100% of Cython code. This is the target for 1.0.

Did you really mean Cython here or Python? I think 100% Python is somewhat
hard to prove. I would expect that we are pretty close to compiling Py2.4
code, and a bit further from compiling 2.5 code (which mainly includes
generator expressions). Not sure about 2.6, which was a heavily moving target
last time I checked.

If you meant Cython, this requires a stable definition of what the Cython
language actually is.


> there are several other things (e.g. the constantly improving buffer  
> support) that are not part of this goal but extremely valuable. I  
> imagine once we hit that target things will still be in flux

I think that's somewhat orthogonal. I can imagine a stable language core with
optional, advanced features. Both can well have different levels of maturity,
both can mature in different release cycles - the more stable ones in the
Python stdlib, and the more experimental or younger ones in independent Cython
releases.


> that inclusion into the Python stdlib will be premature at that  
> point, but worth moving towards.

I'm more thinking in terms of stabilising the core language and major
features. If we shift a bit of our current focus towards that goal, a core
Cython release could even go into Py2.7. (Note that inclusion in Py3.1 would
require migrating the source code to Py3 first, which is still a bit of
additional work, but definitely worth it).


> One thing that is not clear is  
> if a (sufficiently advanced?) user would be able to use the newer  
> Cython with an older version of Python (say, if some projects/modules  
> he needed weren't ported yet.)

I'm not sure where you see the problem here. A user wouldn't replace the core
Cython (i.e. everything else would keep working), but import a separate Cython
install instead.

Just an idea: I would imagine that we will (finally) have to lower-case the
package/module names when we move into the stdlib, but we may keep (at least)
the upper-case Cython package for the stand-alone release. We could then
install with a lower-case package (or both) under Python 2.3-2.6, and with an
upper-case package name on Python versions that already have a packaged Cython.


> There is also the long term question  
> of the parser which is very redundant with the one shipped with  
> Python. (Would we try to migrate over to Python's ASTs? Could that be  
> done without loosing the old-style cdef syntax?)

That's really a long-term question and something that we should discuss with
the CPython developers. If we become an official part of CPython, I imagine
that there will be ways to hook into the existing parser /somewow/.

Stefan