Example needed for declaring, connecting, and using signals and slots

[vdods]

The examples seem to show declarations of QT signals via the qt_signal macro (always empty), but don't show how to connect it to a slot (e.g. something like self.submit_button.clicked().connect(&target.slot_on_submit_button_clicked());). In particular, it would be most useful to see how to define signals and slots that accept custom types as their argument parameters.