Re: [xml] Support for Python

[Gary Benson <gary inauspicious org>]

On Fri, 25 Jan 2002, Daniel Veillard wrote:

> On Thu, Jan 24, 2002 at 04:57:39PM -0800, Dave Kuhlman wrote:
>
> >      * Because I used SWIG's shadow classes, the doc, nodes, and
> >        attributes look, from Python's point of view like instances of
> >        classes. So, walking the DOM tree is very easy and natural.
>
>   Sounds a good idea, I need to look at the generated code. Anover way
> is to make minimal wrappers and build more object oriented classes on
> top of the raw function, defining the classes at the Python level.

It's a lot nicer defining the classes in Python than in C, and you have 
the added benefit that it is a lot easier for someone trying to use the 
library to see how it works.

Also (but don't quote me on this) I'm not sure that you can derive
subclasses from classes defined in C modules. I was was unable to find a C
module that exports a class to test however.

> >      * One qualification is that the interface is at the level of the
> >        libxml, so it's a bit low level. For example, a long running
> >        application would have to call a 'free' method, e.g. xmlFreeDoc,
> >        which is not something a Python programmer would expect to have to
> >        do.
>
>   Hum, keeping reference counting for xmlDocPtr is nearly impossible,
> I doubt there is a workaround. Well this need more thinking, the idea
> of having to call a doc.free() at the end of the processing doesn't sound
> that bad.

If we write the classes in Python then this is trivial -- call xmlFreeDoc 
in the XmlDocumentClass's destructor and let Python's garbage collector 
work out when to do it.

Cheers,
Gary

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