Diez B. Roggisch:
> On second thoughts, a metaclass _might_ help here - but it would be
rather
> elaborate: look in the baseclasses for properties that have getters
and
> setters of the same name as some methods in the current class, and
replace
> them, or create a new property with them (I'm not sure if
descriptors
> allow changing their get/set/del methods). I'm not 100% sure if and
how
> good that works (a quick hack would be easy, but to ship around the
cliffs
> of multiple inheritance requires more careful navigation I fear...)
Maybe you are worrying to much. Here is a quick metaclass solution
which
magically generates properties from methods which name starts with
"get"
or "set":
class MagicProperties(type):
def __init__(cls, name, bases, dic):
prop_names = set(name[3:] for name in dic
if name.startswith("get")
or name.startswith("set"))
for name in prop_names:
getter = getattr(cls, "get" + name, None)
setter = getattr(cls, "set" + name, None)
setattr(cls, name, property(getter, setter))
class Base(object):
__metaclass__ = MagicProperties
def getx(self):
return self._x
def setx(self, value):
self._x = value
class Child(Base):
def getx(self):
print "getting x"
return super(Child, self).getx()
def setx(self, value):
print "setting x"
super(Child, self).setx(value)
c = Child()
c.x = 1
print c.x
This should work well for multiple inheritance too (modulo metaclass
conflicts).
I must say, however, that I never use this idiom (i.e. polluting my
classes
with tons of getters and setters and making properties from them).
I typically use a property factory function, or a custom descriptor.
Michele Simionato
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