[Pyrex] A couple of questions about pyrex

[Yingjie Lan]

--- On Tue, 5/12/09, Robert Bradshaw <robertwb at math.washington.edu> wrote:

> From: Robert Bradshaw <robertwb at math.washington.edu>
> Subject: Re: [Pyrex] A couple of questions about pyrex
> To: "Franck Pommereau" <pommereau at univ-paris12.fr>
> Cc: lanyjie at yahoo.com, pyrex at lists.copyleft.no
> Date: Tuesday, May 12, 2009, 10:54 PM
> On May 12, 2009, at 9:15 AM, Franck Pommereau wrote:
> 
> >> Think further down the road after that is done,
> >> if some day we decided to use 'cdef class'
> for
> >> private class definitions
> > 
> > I don't think that cdef should be interpreted as
> private. But it means
> > that what follows is a native object (ie, implemented
> in C) instead of a
> > Python object.
> 
> +1
> 
> > So if you cdef a type, a variable or a function, there
> is no way to
> > access it from Python because C and Python have
> different conventions
> > for such objects (eg, Python uses name bindings in
> environment and has
> > no proper notion of variable, and calling conventions
> are different also).
> > 
> > On the other hand, if you cdef a class, there is no
> way to see it as a
> > class from C because there is no such notion here. But
> anyway you get a
> > class implemented in C, which is considered a builtin
> class by Python.
> > 
> > Presented this way, it looks fully consistent (at
> least to me).
> 
> 
> cdef statements are used in a variety of declaration
> scenarios (cdef classes, cdef extern blocks, cdef variables
> and methods) and I think the best way to think about them is
> "something at the C level is going on here." In
> any case, the current syntax is not going away/changing
> meaning if just for backwards incompatibility reasons. Also,
> the distinction between classes and types is still large
> enough that on needs to distinguish them, and "explicit
> is better than implicit."
> 

Just like python 3.0, backward compatibility can be handled
in a graceful way -- only a simple replacement, easier than
what has been done with python 3.0, and this can be
done not only with codes to be compiled by pyrex, 
but also with the pyrex/Cython documentation). 
I would say it is quite painless. The main challenge,
of course, is with the implementation. More thought
work need to be done before any action taken.

yingjie