[Swig-user] wrapping at runtime

[<jc...@gm...>]

Hi all,

I've used SWIG to make a Python wrapper for a C++ interface to an
image processing library. I'd like to be able to intercept Python like
this:

  my_object.an_undefined_method_name (a, b, c)

and jump to some C along the lines of:

  PyObject *wrap_unknown_method (char *method_name, PyObject *args,
PyObject *kwargs)

then in that C function I can look up the image processing operation
in a table, convert the Python arguments, call the operation, convert
the results back to Python, and return. I want to do this so I can
handle plugins nicely (new operations added to the image processing
library at runtime) and so I can reduce the (currently *huge*) size of
the wrapper.

Can anyone suggest techniques for doing this? I'm thinking of using
SWIG to generate a base Python class, then (by hand) subclassing that
and doing the intercept myself in the derived class. Does that sound
sensible? Is there a neater way? Could I inject some code into the
right place in the SWIG-generated wrapper somehow?

Many thanks for any ideas,

John