Stefan Seefeld <[EMAIL PROTECTED]> writes: > Is there anything wrong with 'exec source in a, b' where > a and b are distinc originally empty dictionaries ? Again, > my test code was > > class Foo: pass > class Bar: > foo = Foo > > and it appears as if 'Foo' was added to 'a', but when evaluating > 'foo = Foo' the interpreter only looked in 'b', not 'a'.
No, it's the other way round. Foo is added in b since bindings are done in the local scope. Your case is a bit more complicated, though. Here's what I think happens: class Foo is bound in b, the locals dictionary, so there is no reference to Foo in the globals dictionary. The body of class B is executed with it's own new locals dictionary. That locals dictionary will effectively be turned into Bar.__dict__ when the class object is created. When "foo = Foo" is executed, Foo is first looked up in that new locals dictionary. That fails, so it's also looked up in the globals dictionary a. That fails as well because Foo was bound in b. The final lookup in the builtins also fails, and thus you get an exception. Bernhard -- Intevation GmbH http://intevation.de/ Skencil http://skencil.org/ Thuban http://thuban.intevation.org/ -- http://mail.python.org/mailman/listinfo/python-list
