Is there a way to create an "actual" Qt property in PyQt?

[Phil Thompson]

On 22/10/2020 22:12, Ales Erjavec wrote:
>> ...
>> Note that I don't really care for some further lines in the class
>> definition/constructor; what I'd really prefer is to always have a
>> consistent way to access properties if they *also are* Qt properties.
> 
> A while ago I had a similar thought of subverting the property
> descriptor protocol:
> 
> 
> class Q_Property(pyqtProperty):
>     """
>     A property descriptor that more closely resembles the
>     Q_PROPERTY macro.
> 
>     Encourage a coding style which is consistent with Qt.
> 
>     Example:
>     >>> class Foo(QObject):
>     ...     _bar = 0
>     ...     def bar(self):
>     ...         return self._bar
>     ...     def setBar(self, bar):
>     ...         self._bar = bar
>     ...     bar = Q_Property(int, fget=bar, fset=setBar)
> 
>     >>> obj = Foo()
>     >>> obj.setBar(2)
>     >>> obj.bar()
>     2
>     >>> obj.setProperty("bar", 42)
>     True
>     >>> obj.property("bar")
>     42
>     >>> obj.bar()
>     42
>     """
>     def __get__(self, obj, cls=None):
>         # Simply return the contained (bound) fget method
>         return self.fget.__get__(obj, cls)
> 
>     def __set__(self, obj, value):
>         raise TypeError
> 
>     # these do not work
>     def setter(self, f):
>         raise RuntimeError
> 
>     def getter(self, f):
>         raise RuntimeError

IMHO, that's not a property.

> But have not actually used it anywhere. Usually I just
> use the convention of adding a underscore suffix to the
> property member i.e.
> 
> bar_  = pyqtProperty(int, fget=bar, fset=setBar)

Q_PROPERTY is a way of implementing in C++ something that is a property 
in QML and Qt Designer. It is not a property in C++.

Python properties are proper properties.

Phil