>> None is moving slowly toward becoming a true constant. Perhaps the >> same should be true of True and False.
Guido> Problem with this is that there's currently lots of code out Guido> there that was recently modified to read
Guido> try: Guido> True Guido> except NameError: Guido> True = 1 Guido> False = 0
Guido> That would become a syntax error if True/False were true Guido> constants. :-(
Hmmm... Those code blocks would only be executed on older versions of the interpreter. Is there some way to use that knowledge to finesse the problem? It would be a real hack, but if the compiler recognized precisely the above construct (or at least assignment in an except block guarded by NameError), it could shut up about the assignment.
You would have to do a fairly significant analysis of all code in the module to know that there are no assignments to globals True or False anywhere, *and* you would have to add a heuristic to cope with the very code fragment above, *and* you would have to have a firm belief that no other code would do import foo foo.True = "True" I've often mentioned the first item above (per-module code analysis) as doable, but it's not done. --Guido van Rossum (home page: http://www.python.org/~guido/)