[PyKDE] QModelIndex and PyQT

[Allen Bierbaum]

I apologize if this has been discussed here before, I searched the
mailing list and didn't find anything.

I am beginning to use PyQT4 and I have run into some major headaches
trying to use QModelIndex.  The problem stems from the fact that as
far as I can tell with the PyQT bindings it is not possible to attach
a reference to a python object to the index to then later be used by
data(), parent(), or any other methods.

In C++ this is possible (and seems to be recommended usage) by using
the internalPointer() method of ModelIndex.  This works for C++
because the internal pointer is stored as a void pointer that the
developer knows the true type of and they can just cast it to the
correct type to use it.

Without this capability all use of QModelIndex in PyQT, when I use
TreeViews I have found myself contorting my data models quite a bit to
make things limp along.   I am currently  funneling all index lookups
through a manually maintained map from int id's to python objects.  Is
this how other people are also working with QT4 models?

I was surprised that there was no way (that I know of) to attach a
python object to a QModelIndex.  It seems from the QT documentation
that this is the intent of how indexes are to be used in C++, but
there is no corresponding way to do this in Python.

I was wondering though, would it be possible to expand the PyQT
bindings a bit and add two methods:

QModelIndex.internalPyObj()
QAbstractItemModel.createIndexPy(int, int, pyobj)

I think it could be implemented by casting from PyObject* to void*
behind the scenes and passing through to the existing
internalPointer() C++ interface.  This would make working in Python
much easier while still preserving the intent of the QModelIndex
interface.

Any comments?  Am I missing some easy way to do this already?

Thanks,
Allen