Re: [boost] Re: What are the future plans for Boost.Python?

From: John Max Skaller (skaller_at_[hidden])
Date: 2001-06-15 19:30:33

David Abrahams wrote:

> C++ functions which are exposed to Python get an argument conversion layer
> which is based on the argument types (using template type deduction). So, if
> there is a conversion from the passed Python type to the C++ argument type,
> the function call succeeds with that conversion. If you want your C++
> function to see a "raw" python type, there are several options:
> 
> 1. Use a PyObject* argument. Its type conversion is the identity
> 2. Use a boost::python::ref, which does the reference-counting part for you
> 3. Use a specific python type wrapper (e.g. boost::python::tuple) from
> boost/python/objects.hpp.

        I see. Thanks! I'd never considered something
other that (1). So I guess there is a predefined mapping
from Python types to C++ types?

        In the bindings I created, the system didn't handle
methods at all. It just hooked get_attr, which the
user had to implement to call the right C++ function.

        That is, I defined an abstract class corresponding
to a PyObjct, with virtual functions that were called from C for 
each entry in the Python 'virtual table'. Unfortunately,
that doesn't work too well, since Python checks if the
table entries are null or not: for my abstraction,
they never were. About then, I gave up. :-)

-- 
John (Max) Skaller, mailto:skaller_at_[hidden]
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