[Python-Dev] LZMA compression support in 3.3

[Nick Coghlan]

On Sun, Aug 28, 2011 at 1:40 AM, Antoine Pitrou <solipsis at pitrou.net> wrote:
> On Sun, 28 Aug 2011 01:36:50 +1000
> Nick Coghlan <ncoghlan at gmail.com> wrote:
>> On Sun, Aug 28, 2011 at 1:15 AM, "Martin v. Löwis" <martin at v.loewis.de> wrote:
>> > This is exactly what I worry about. I think adding file I/O to bz2 was a
>> > mistake, as this doesn't integrate with Python's IO library (it used
>> > to, but now after dropping stdio, they were incompatible. Indeed, for
>> > Python 3.2, BZ2File has been removed from the C module, and lifted to
>> > Python.
>> >
>> > IOW, the _lzma C module must not do any I/O, neither directly nor
>> > indirectly (through liblzma). The approach of gzip.py (doing IO
>> > and file formats in pure Python) is exactly right.
>>
>> PEP 399 also comes into play - we need a pure Python version for PyPy
>> et al (or a plausible story for why an exception should be granted).
>
> The plausible story being that we basically wrap an existing library?
> I don't think PyPy et al have pure Python versions of the zlib or
> OpenSSL, do they?
>
> If we start taking PEP 399 conformance to such levels, we might as well
> stop developing CPython.

It's acceptable for the Python version to use ctypes in the case of
wrapping an existing library, but the Python version should still
exist.

Cheers,
Nick.

-- 
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia