On Tue, 27 Feb 2007 20:59:03 +0000, Alan Isaac wrote:
> "Steven D'Aprano" <[EMAIL PROTECTED]> wrote in message
> news:[EMAIL PROTECTED]
> class Difficult(object):
> def __setattr__(self, name, value):
> if self.__dict__.has_key(name):
> print "'%s' exists as an instance attribute" % name
> self.__dict__[name] = value
> elif self.__class__.__dict__.has_key(name):
> print "'%s' exists as a class attribute" % name
> self.__class__.__dict__[name] = value
> else:
> print "Can't create new attributes, 'cos I said so!"
>
>
>
> But this prevents setting attributes during initialization,
> so it does not meet the spec.
What, you expect us to do everything for you? *wink*
If you want the class to change behaviour after initialisation, you have
to code it to do so. The easy, but inelegant, way is to set a flag.
Finding an elegant way to do so is a little like asking for an elegant way
to scrub a septic tank clean. But one way might be to change the class
after initialisation:
class Parrot(object):
def __init__(self, data):
self.data = data
self.__class__ = Annoying
class Annoying(Parrot):
def __setattr__(self, name, value):
print "Annoy the user."
>>> x = Parrot(5)
>>> x.data
5
>>> x.data = 7
Annoy the user.
>>> x.data
5
--
Steven D'Aprano
--
http://mail.python.org/mailman/listinfo/python-list
