Python decorators are fun to use, but I appear to have hit a wall due to the way arguments are passed to decorators. Here I have a decorator defined as part of a base class (the decorator will access class members hence it will require the self parameter).
class SubSystem(object):
def UpdateGUI(self, fun): #function decorator
def wrapper(*args):
self.updateGUIField(*args)
return fun(*args)
return wrapper
def updateGUIField(self, name, value):
if name in self.gui:
if type(self.gui[name]) == System.Windows.Controls.CheckBox:
self.gui[name].IsChecked = value #update checkbox on ui
elif type(self.gui[name]) == System.Windows.Controls.Slider:
self.gui[name].Value = value # update slider on ui
...
I've omitted the rest of the implementation. Now this class is a base class for various SubSystems that will inherit from it - some of the inherited classes will need to use the UpdateGUI decorator.
class DO(SubSystem):
def getport(self, port):
"""Returns the value of Digital Output port "port"."""
pass
@SubSystem.UpdateGUI
def setport(self, port, value):
"""Sets the value of Digital Output port "port"."""
pass
Once again I have omitted the function implementations as they are not relevant.
In short the problem is that while I can access the decorator defined in the base class from the inherited class by specifiying it as SubSystem.UpdateGUI, I ultimately get this TypeError when trying to use it:
unbound method UpdateGUI() must be called with SubSystem instance as first argument (got function instance instead)
This is because I have no immediately identifiable way of passing the self parameter to the decorator!
Is there a way to do this? Or have I reached the limits of the current decorator implementation in Python?