You are just deflecting now. You made the claim that somehow macros would have made the python 2 to 3 migration easy. You are yet to demonstrate which of the migration issues would have been solved by macros.
dict.keys() returning something different from what it used to isn't a syntactic change; it's a change in function behavior. Since macros handle syntax, they aren't applicable to a function semantics change.
What we might do here is to use two different keys symbols in different packages. We can have a ver2:keys and ver3:keys and control which of these dict.keys() uses in some scope. But that's not macros.
The point is that with macros, we can do the same thing with the syntax of the language; it's a library feature that we can subject to versioning. Old syntax can be supported side by side with new syntax. So then since we have a way to have old syntax and old API semantics, which is pretty much everything, we can have a nice migration path.
> dict.keys() returning something different from what it used to isn't a syntactic change; it's a change in function behavior. Since macros handle syntax, they aren't applicable to a function semantics change.
Now you are telling me something I told you in the first place.
> What we might do here is to use two different keys symbols in different packages. We can have a ver2:keys and ver3:keys and control which of these dict.keys() uses in some scope. But that's not macros.
Right. So like I said, macros won't have helped, at all.
> Old syntax can be supported side by side with new syntax.
Creating a Frankenstein's monster was never the goal. And besides, they already had tools for code which can run both on 2 and 3.
