[Python-Dev] cffi in stdlib

Nick Coghlan ncoghlan at gmail.com
Wed Feb 27 13:39:30 CET 2013

On Wed, Feb 27, 2013 at 7:06 PM, Maciej Fijalkowski <fijall at gmail.com> wrote:
>> 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.

C itself shouldn't be *too* bad - it's trying to parse C++ that is
truly insane (which is why Dave Beazley explicitly warned Maciej and
Armin away from that based on his experience with SWIG).

Looking at pycparsing more closely though, there may be a problem with
the C preprocessing step on Windows. While on Linux it uses the system
"cpp", for Windows it currently bundles a copy of the LCC
preprocessor, which may pose licensing challenges
(https://github.com/drh/lcc/blob/master/CPYRIGHT). However, this
concern may not be applicable to cffi: given cffi's requirement for a
full external C compiler to actually *create* the C extension modules
during development, and the ability to retrieve everything necessary
directly from the created C extension when no C compiler is available,
it seems there would be no reason to ever need the bundled C
preprocessor. So we simply don't ship it, and the LCC license becomes


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

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