[pypy-dev] offtopic, ontopic, ...

[Antonio Cuni]

On 02/14/2012 06:56 PM, Stefan Behnel wrote:
> Ok, then I take it that this would be the preferred Python+FFI approach for
> interfacing, right? ctypes is out of the loop?

note that there are at least two different levels to interface with C code.

The first is using rffi, which lets you to call C code from RPython. Calls to 
rffi functions are translated into C calls at translation time.

Then, there is the ctypes-like approach, which lets you to call C from 
applevel code, which is basically a layer on top of libffi.
The ctypes approach has some pretty important advantages, e.g. you don't need 
a compiler, people don't need to learn another language, the development is 
faster, etc.

On the other hand, I think that most of us agree that the ctypes interface is 
terrible. What I would like is an ffi module which is applevel but with a much 
nicer interface. And, the JIT compiler can turn these calls into very 
efficient machine code.

We do need both alternatives in PyPy, if anything because ctypes or this 
yet-to-come "ffi" module need to be implemented in RPython and thus depends on 
rffi.
However, once it's ready the ffi module should ideally be powerful enough to 
interface with all the C code out there.

ciao,
Anto