[Swig-user] addmethods with %include and %template

[Robert J. H. <rjh...@cs...>]

I have a large set of header files which specify a set of template
classes.  In C++, I have operator<< overloaded so that you can dump an
instance of this templatized class to an output stream of your choice.

I understand I can get the same behavior from Python if in SWIG I use
addmethod to add a __str__ method, but this strikes me as somewhat
dangerous.  All of the examples I've seen have included the class to be
wrapped in the swig.i file itself, with addmethod used in the swig.i
file to extend the class.

Given the size of my headers, this seems to be a very bad idea.  If I
make adjustments to my headers, I don't want to have to remember to
adjust the swig.i file to make sure the two remain in sync.  Right now,
the swig.i file is very simple and I'd love to keep it that way.

In each of the Annealer classes specified in my swig.i file (listed
below), there is a .solution() method which returns a std::string
containing human-readable output.  This would probably be the basis for
any __str__ method.

Can anyone give guidance on how to proceed in a way that will leave me
with a terse, maintainable swig.i file?


=====

%module Djinni
%{
#include "Annealer.h"
#include "TSPRoute.h"
#include "Penalties.h"
%}

%include "Annealer.h"
%include "TSPRoute.h"
%include "Penalties.h"

%template(TSP) TSPRoute<TSPTWWorld>;
%template(CA_TSP) Annealer<Compressed, TravelingSalesman>;
%template(SA_TSP) Annealer<Simulated, TravelingSalesman>;

=====