July 1, 2006
6:09 a.m.
At 07:04 PM 6/30/2006 -0400, Andrew Koenig wrote:
However, if I write
def g(): return x x = 42 g()
the result is 42. With lexical scoping, I believe it should be undefined.
The reason is that when the compiler encounters the definition of g, variable x is not yet bound, and there is nothing in the body of g that would bind it. Therefore, g requires a binding to exist at the time it is compiled; because no such binding exists, this example would be an error (at compile time) under lexical scoping.
That sounds like a bug, not a feature. It's frequently useful to have forward references in function bodies to names that are not yet globally bound, e.g. for classes, or mutually-recursive functions.