[Cython] Buffer type specification (CEP 514) in @cython.locals() in .pxd

[Matěj Laitl]

Hi list,
it has been unusually quiet here so it's time to speak up.

How hard would it be to implement support for specifying buffer dtype (and 
friends) in @cython.locals() in a .pxd file? Following code (in a .pxd file)

cimport numpy
@cython.locals(local1 = numpy.ndarray[double])
cdef double f()

currently yields "test.pxd:4:32: Not a type" error. The problem is that one 
currently cannot make use of buffer access optimisation for local variables in 
pure python mode. I use pure mode extensively in my project [1].

[1] https://github.com/strohel/PyBayes

I understand that it has no sense in .py files as type type is not usually 
subscriptable.

On the same note, is there a plan to implement fast buffer access for class 
variables? ;) (this is obviously not that crucial)

Regards and keep up the good work!
   Matěj Laitl