Improve the NumPy Support by iterables

Working example, by overriding cppgenerator:

>>> from PySide2 import *
>>> QtCore.QUrl.fromStringList(("asd", "def"))
[PySide2.QtCore.QUrl('asd'), PySide2.QtCore.QUrl('def')]
>>> def func(lis):
...   for thing in lis:
...      yield thing
...
>>> QtCore.QUrl.fromStringList(func(["asd", "def"]))
[PySide2.QtCore.QUrl('asd'), PySide2.QtCore.QUrl('def')]

Also working, by overriding shibokengenerator

>>> QtGui.QMatrix4x4(func(range(16)))

And all other QMatrix sizes as well:

>>> QtGui.QMatrix2x2(func(range(4)))
>>> QtGui.QMatrix2x3(func(range(6)))

The PySequence cases seem to be quite completely covered.
Supporting lists and QVector is not yet clear and needs
more research.

Note.. QtOpenGLFunctions is not tested at all and nothing works
    on macOS, segfault. Ignored for now!

A simple numpy test shows how versatile this solution is.
We now need to improve signatures and error messages
to optimize the experience.

Task-number: PYSIDE-795
Change-Id: I195cd46cf47c2eb83276fe48fce8e6070cf30fda
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>

1 files changed, 4 insertions, 2 deletions

diff --git a/sources/pyside2/PySide2/glue/qtgui.cpp b/sources/pyside2/PySide2/glue/qtgui.cpp
index 5be8cc287..d2480e99e 100644
--- a/sources/pyside2/PySide2/glue/qtgui.cpp
+++ b/sources/pyside2/PySide2/glue/qtgui.cpp
@@ -455,10 +455,12 @@ QPoint p(%CPPSELF.%FUNCTION_NAME(%1));
 // @snippet qmatrix-map-point
 
 // @snippet qmatrix4x4
-if (PySequence_Size(%PYARG_1) == 16) {
+// PYSIDE-795: All PySequences can be made iterable with PySequence_Fast.
+Shiboken::AutoDecRef seq(PySequence_Fast(%PYARG_1, "Can't turn into sequence"));
+if (PySequence_Size(seq) == 16) {
     float values[16];
     for (int i=0; i < 16; ++i) {
-        PyObject *pv = PySequence_Fast_GET_ITEM(%PYARG_1, i);
+        PyObject *pv = PySequence_Fast_GET_ITEM(seq.object(), i);
         values[i] = PyFloat_AsDouble(pv);
     }