Antoon Pardon <[EMAIL PROTECTED]> writes: > Op 2005-11-03, venk schreef <[EMAIL PROTECTED]>: > > You see, > > The seen behavior is due to the result of python's name > > binding,scoping scheme. > > I know what causes the behaviour. But I still think it is > not sane behaviour. > > > > ... > > > > the same thing happens in the case of b.a = b.a + 2 .... search for b.a > > not found, read the value from the enclosing scope (of the class > > object).... then assign b.a to the local scope, with the value 3. > > This is an explanation depending on a specific implementation. > > Now can you give me a language design argument that supports the > idea that in "b.a = b.a + 2" b.a refers to two different objects. > > And even if you could do that, can you give such an argument that > in "b.a += 2" that one occurence of b.a should refer to two different > objects.
Your problem is a namespace conflict together with a certain stubborness about lookup order :-) It is really simple. When you say b.a then the instance variable 'a' is looked up first. If it does not exist then a class variable lookup is done. Remember, Python is a dynamic language. It is all according to how things have been in Python for a long time. The real issue here is that you should propery name class variables so that there can't be any confusion about class or instance scope. I use all uppercase identifiers for class variables for example. S. -- http://mail.python.org/mailman/listinfo/python-list
