On Fri, Jul 1, 2016 at 10:27 PM, Veek. M <vek.m1...@gmail.com> wrote: > Trying to make sense of this para: > > -------------------------------------------------- > Also, the attribute name used by the class to hold a descriptor takes > prece- dence over attributes stored on instances. > > In the previous example, > this is why the descriptor object takes a name parameter and why the > name is changed slightly by inserting a leading underscore. In order > for the descriptor to store a value on the instance, it has to pick a > name that is different than that being used by the descriptor itself > --------------------------------------------- > Under normal circumstances, when I do an attribute lookup: > x = Foo() > x.a > he will first check 'x' then Foo. > > Is he say that Descriptors are a special case where Foo is checked > first,
It depends whether it's a "data descriptor" or not. A data descriptor is one that defines at least one of __set__ or __delete__, not just __get__. Data descriptors take precendence over instance attributes. Instance attributes take precedence over non-data descriptors. > then what - Base classes..? Checking base classes is part of checking the class. If a base class has a data descriptor, that will likewise take precedence over the instance attribute, which will likewise take precedence over non-data descriptors in the base class. > or does he hop back to look in the > instance? How is C3 Linearization altered? It's not. > Additionally, > class Foo: > def __init__(self, name, value): > self.name = name > > cannot be done because > x = Foo('bar', 10) > > x.bar will..? attribute in class takes precedence.. great, isn't that > what we want? I don't understand what you're asking here or what this example has to do with descriptors. -- https://mail.python.org/mailman/listinfo/python-list