Metaclass Recipe: Generating Bitfield Properties

ENABLED, SIMPLE, SUNKEN, RAISED, TRANSPARENT = 1, 2, 4, 8, 16

class Widget(object):
    style = 0

    enabled = property(
        lambda self: bool(self.style & ENABLED),
        lambda self, v: setattr(self, 'style',
            self.style | ENABLED if v else self.style ^ ENABLED),
    )
    simple = property(
        lambda self: bool(self.style & SIMPLE),
        lambda self, v: setattr(self, 'style',
            self.style | SIMPLE if v else self.style ^ SIMPLE),
    )
    sunken = property(
        lambda self: bool(self.style & SUNKEN),
        lambda self, v: setattr(self, 'style',
            self.style | SUNKEN if v else self.style ^ SUNKEN),
    )
    raised = property(
        lambda self: bool(self.style & RAISED),
        lambda self, v: setattr(self, 'style',
            self.style | RAISED if v else self.style ^ RAISED),
    )
    transparent = property(
        lambda self: bool(self.style & TRANSPARENT),
        lambda self, v: setattr(self, 'style',
            self.style | TRANSPARENT if v else self.style ^ TRANSPARENT),
    )

w = Widget()
w.enabled = True
print w.style

w.sunken = True
print w.style

w.transparent = True
print w.style

w.sunken = False
print w.style