Re: Declaring attributes in PyCXX

[Barry S. <ba...@ba...>]

On 7 Apr 2014, at 12:42, Burak Kahraman <bur...@la...> wrote:

> Hi Barry,
> 
> I just started to write my own Python extensions and immediately switched to your library because of several positive posts on stackoverflow.
> I really like it so far, but I have a very basic problem. I added my attributes by overriding getattro() as in the examples, but the thing is I want to see these attributes when using dir() on my object. So I have to declare these somehow.
> With the regular functions I could create a static array of PyGetSetDef() (defining the attribute name and getter and setter functions) and assign it to tp_getset.
> This doesn't work in my subclass of ExtensionModule, as I don't have access to the protected variable PythonType::tp_getset.
> I also started a topic on stackoverflow without any luck yet :-\
> 
> Thanks for your great work and it would be nice to hear back from you.
> 

The trick is that python asks for the value of __members__.

In your code return a list of the names you want to see in dir(your_obj).

This is a cut down version of what I did in pysvn code to support dir().

Py::Object pysvn_client::getattr( const char *_name )
{
    std::string name( _name );

    if( name == "___members__" )
    {
        Py::List members;

        members.append( "callback_get_login" );
        members.append( "callback_notify" );

        return members;
    }

    if( name == "callback_get_login" )
        return m_context.m_pyfn_GetLogin;

    return getattr_default( _name );
}

Barry





> Best,
> Burak
> 
> -- 
> Burak Kahraman
> Software Developer
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