Generators through the C API

[Stefan Behnel]

Duncan Booth schrieb:
> Lucas P Melo <lukepadawan at gmail.com> wrote:
> 
>> Hello, I'm a total noob about the C API. Is there any way to create a 
>> generator function using the C API? I couldn't find anything like the 
>> 'yield' keyword in it.
>>
>> Thanks in advance.
> 
> You define a new type with tp_flags including Py_TPFLAGS_HAVE_ITER. 
> Anything that would be a local variable in your generator needs to become 
> an attribute in the type.
> 
> The tp_init initialization function should contain all the code up to the 
> first yield, tp_iter should return self and tp_iternext should execute code 
> up to the next yield.

This is pretty easy to do in Cython (or Pyrex), BTW. Just write a class
with an __iter__ and __next__ method, and Cython will generate the C-API
code as expected.

http://docs.cython.org/docs/special_methods.html#iterators

Note that Cython doesn't currently support the "yield" statement, but
that's certainly on the ToDo list.

http://trac.cython.org/cython_trac/ticket/83

Stefan