> > Hi list, I've been following a discussion on a new way of defining > > getters and setters on python-dev and just can't understand what the > > purpose is. Everybody agreed on the dev list that this is a good idea > > so I guess it must be right :) > > > > The whole thing started with this post of Guido: > > > > http://mail.python.org/pipermail/python-dev/2007-October/075057.html > > > > which then continued into November. Basically, the idea is that using > > the new way a setter can be added to property that was read-only > > before. But if I have this already, > > > > class C: > > @property > > def attr( self ): return self._attr > > > > what prevents me using the following for adding a setter for attr: > > > > class C: > > def attr( self ): return self._attr > > def set_attr( self, value ): self._attr = value > > attr = property( attr, set_attr ) > > > > In other words all I needed to do is delete @property, write the > > setter method and add attr = property( attr, set_attr ). What does the > > new way improve on this? > > It prevents namespace-pollution in a clever way. By first defining the > getter, the @propset-decorator will augment the already createt property > and return it. > > Thus you don't end up with a > > set_attr > > function. > > > Other, more complex recipes to do the same look like this and are much > harder to grasp: > > > @apply > def my_property() > def fget(self): > return self._value > def fset(self, value): > self._value = value > return property(**locals()) > > So the proposed propset-decorator certainly makes things clearer. > > Diez
Aaaaaha :) Makes sense indeed. Thanks, Daniel -- http://mail.python.org/mailman/listinfo/python-list
