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

Stefan Behnel stefan_ml at behnel.de
Sun Aug 28 08:50:21 CEST 2011

Dan Stromberg, 27.08.2011 21:58:

On Sat, Aug 27, 2011 at 9:04 AM, Nick Coghlan wrote:

On Sun, Aug 28, 2011 at 1:58 AM, Nadeem Vawda wrote:

On Sat, Aug 27, 2011 at 5:52 PM, Nick Coghlan wrote:

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.

I'm not too sure about that - PEP 399 explicitly says that using ctypes is frowned upon, and doesn't mention anywhere that it should be used in this sort of situation. Note to self: do not comment on python-dev at 2 am, as one's ability to read PEPs correctly apparently suffers :) Consider my comment withdrawn, you're quite right that PEP 399 actually says this is precisely the case where an exemption is a reasonable idea. Although I believe it's likely that PyPy will wrap it with ctypes anyway :) I'd like to better understand why ctypes is (sometimes) frowned upon. Is it the brittleness? Tendency to segfault?

Maybe unwieldy code and slow execution on CPython?

Note that there's a ctypes backend for Cython being written as part of a GSoC, so it should eventually become possible to write C library wrappers in Cython and have it generate a ctypes version to run on PyPy. That, together with the IronPython backend that is on its way, would give you a way to write fast wrappers for at least three of the major four Python implementations, without sacrificing readability or speed in one of them.

Stefan

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