On Fri, Jan 18, 2013 at 3:52 PM, Steven D'Aprano <steve@pearwood.info> wrote:
Another question: what happens if the constant expression can't be evaluated until runtime?
x = random.random() const k = x + 1
y = k - 1
What value should the compiler substitute for y?
That should be disallowed. In the declaration of a constant, you have to use only what can be handled by the constants evaluator. As a rule of thumb, it'd make sense to be able to use const with anything that could safely be evaluated by ast.literal_eval. As to the issues of rebinding, I'd just state that all uses of a particular named constant evaluate to the same object, just as would happen if you used any other form of name binding. I don't have the post to hand, but wasn't there a project being discussed recently that would do a lot of that work automatically? ChrisA