[PyQt] [PyKDE] KTextEditor interface classes

Paul Giannaros paul at giannaros.org
Sat Aug 30 00:19:24 BST 2008

On Fri, Aug 29, 2008 at 11:47 PM, Jim Bublitz <jbublitz at nwinternet.com> wrote:
> On Friday 29 August 2008 15:02, Paul Giannaros wrote:
>> KTextEditor works with an interface class -- implementors of the
>> interface subclass
>> KTextEditor::View and KTextEditor::Document, with the subclasses also
>> inheriting from any interfaces that they choose to support. This is a
>> problem -- I can't see
>> a way to cast to the required type.
>> Even though I can check at run-time whether my view implements an interface
>> with something like:
>> >>> document = Kate.application().documentManager().documents()[0]
>> >>> view = document.activeView()
>> >>> view.inherits('KTextEditor::ConfigInterface')
>> True
>> I cannot use anything to cast to the appropriate type to get at the
>> methods provided
>> by the interface.
>> Is there a solution to this problem?
> Are the parent classes also wrapped in your module?

Firstly, it's not my module: ktexteditor is part of PyKDE4! Most of the
interface classes are wrapped, yes (it looks like some may be
missing, though; I can see KTextEditor::AnnotationInterface exists
but no sip binding for it exists according to websvn).

> If they are, you can use %ConvertToSubClassCode (CTSCC) - see it's use in
> PyKDE or PyQt for examples and the sip docs (not all PyKDE classes have
> inherits() available, so they use dynamic_cast; PyQt code uses inherits()).
> For example, if a call creates a QWidget but returns (in C++) a QObject,
> CTSCC will "cast" the returned object to QWidget in the Python program.

I'm not sure how this will help. I don't want the KTextEditor::View object
to always be returned to me as a KTextEditor::ConfigInterface. I need some
way to get at a ConfigInterface (and a CursorInterface, SearchInterface, etc)
from a View instance. I'd be happy if View objects had a method like
configInterface() to return the interface where available.

> Otherwise there are ways to cast within Python using sip functions (see the
> sip docs), but they probably aren't what you want.

Unfortunately not. sip.cast only lets you cast to instances of superclasses.


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