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[Python-Dev] cffi in stdlib

Ronald Oussoren ronaldoussoren at mac.com
Wed Feb 27 10:18:02 CET 2013 
On 27 Feb, 2013, at 10:06, Maciej Fijalkowski <fijall at gmail.com> wrote:

> On Wed, Feb 27, 2013 at 9:29 AM, Ronald Oussoren <ronaldoussoren at mac.com> wrote:
>> 
>> On 26 Feb, 2013, at 16:13, Maciej Fijalkowski <fijall at gmail.com> wrote:
>> 
>>> Hello.
>>> 
>>> I would like to discuss on the language summit a potential inclusion
>>> of cffi[1] into stdlib.
>> 
>> The API in general looks nice, but I do have some concens w.r.t. including cffi in the stdlib.
>> 
>> 1. Why is cffi completely separate from ctypes, instead of layered on top of it? That is, add a utility module to ctypes that can parse C declarations and generate the right ctypes definitions.
> 
> Because ctypes API is a mess and magic. We needed a cleaner (and much
> smaller) model.

The major advantages of starting over is probably that you can hide the complexity and that opens opportunities for optimizations. That said, I'm not convinced that ctypes is unnecessarily complex.
> 
>> 
>> 2. Cffi has a dependencies on pycparser and that module and its dependencies would therefore also be added to the stdlib (even if they'd be hidden in the cffi package)
> 
> Yes. pycparser and ply.

Which aren't part of the stdlib right now.

> 
>> 
>> 3. Cffi basicly contains a (limited) C parser, and those are notoriously hard to get exactly right. Luckily cffi only needs to interpret declarations and not the full language, but even so this can be a risk of subtle bugs.
> 
> It seems to work.

That's not a confidency inspiring comment :-).  That said,  I use a hacked up fork of pycparser to parse Apple's Cocoa headers for PyObjC and it appears to work fine for that.

> 
>> 
>> 4. And finally a technical concern: how well does cffi work with fat binaries on OSX? In particular, will the distutils support generate cached data for all architectures supported by a fat binary?
> 
> no idea.

That's somehting that will have to be resolved before cffi can be included in the stdlib, fat binaries are supported by CPython and are used the binary installers.

Ronald
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