[C++-sig] Adding a method on the fly

[Kelly Burkhart]

On 4/5/06, Stefan Seefeld <seefeld at sympatico.ca> wrote:
>
> Kelly Burkhart wrote:
> > Is there a way to do what I'm looking for with v1.33.1?
>
> I'm not sure what bits you were particularly interested in.
> I showed the 'exec' function only as an example (because constructing
> and running a python object in pure C++ would be pretty pointless. :-) ).
>
> You were asking about binding a function to an object, which doesn't
> require 'exec'.
>

I'm trying to programatically create a python function and bind it to a C++
object.  Using your code above as an example, I belive it may be something
like this:


>From C++:

using namespace boost;
using namespace boost::python;

class Foo {...};

void mkMethod( object self, const std::string &name ) {
    // Get Foo instance namespace
    object selfdict(self.attr("__dict__"));

    // Define class
    exec(str(format("def %s( arg ): print arg") % name.c_str),
         selfdict, selfdict);
}
...
// Wrap class Foo
class_<Foo> cls("Foo");

// Wrap mkMethod function
def("mkMethod", mkMethod);

// Attach mkMethod to Foo
cls.setattr("mkMethod",&mkMethod)


>From Python:

from foomod import Foo
f = Foo()
f.mkMethod('newmethod')

# now a brand new method of f exists
f.newmethod(123)


-K
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