[Python-Dev] LZMA compression support in 3.3 (original) (raw)

Nick Coghlan ncoghlan at gmail.com
Sat Aug 27 17:52:51 CEST 2011

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

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