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]

Re: embedding python: simulating sequence get item / set item methods

Johannes Zellner <johannes@zelln er.org> wrote:
[color=blue]
> 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?[/color]

Sure, see the details at <http://docs.python.org/api/newTypes.html> and
consider that what you want will need to go into a PyMappingMethod s or
PySequenceMetho ds 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