embedding python: simulating sequence get item / set item methods

[Johannes Zellner]

Hello,

when embedding python: how can I create a type which simulates item
getters and setters? Something like this:

void setter(PyObject* self, int i, PyObject new_value)
{
// do something
}

PyObject* getter(PyObject* self, int i)
{
// do something
return something;
}

and I'd like the first method called if (from a python script):

my_list[i] = value

and the second method, if accessing the list

print str(my_list[i])

Is this possible?

--
Johannes

[Alex Martelli]

Johannes Zellner <jo******@zellner.org> wrote:

Hello,

when embedding python: how can I create a type which simulates item
getters and setters? Something like this:

void setter(PyObject* self, int i, PyObject new_value)
{
// do something
}

PyObject* getter(PyObject* self, int i)
{
// do something
return something;
}

and I'd like the first method called if (from a python script):

my_list[i] = value

and the second method, if accessing the list

print str(my_list[i])

Is this possible?

Sure, see the details at <http://docs.python.org/api/newTypes.html> and
consider that what you want will need to go into a PyMappingMethods or
PySequenceMethods structure -- not well documented online, but just take
a look in the Python sources at the way the type objects for lists &c
are defined, and take it from there.
Alex