[Python-Dev] LZMA compression support in 3.3

[Stefan Behnel]

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 Consider my comment withdrawn, you're quite right that PEP 399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