Darren New wrote: > Andreas Rossberg wrote: > >> Yes, technically you are right. But this makes a pretty weak notion of >> mutability. All stateful data structures had to stay within their >> lexical scope, and could never be passed to a function. > > Not really. The way Hermes handles this is with destructive assignment. > Each variable holds a value, and you (almost) cannot have multiple > variables referring to the same value.
OK, this is interesting. I don't know Hermes, is this sort of like a dynamically checked equivalent of linear or uniqueness typing? > If you want to assign Y to X, you use > X := Y > after which Y is considered to be uninitialized. If you want X and Y to > have the same value, you use > X := copy of Y > after which X and Y have the same value but are otherwise unrelated, and > changes to one don't affect the other. Mh, but if I understand correctly, this seems to require performing a deep copy - which is well-known to be problematic, and particularly breaks all kinds of abstractions. Not to mention the issue with uninitialized variables that I would expect occuring all over the place. So unless I'm misunderstanding something, this feels like trading one evil for an even greater one. - Andreas -- http://mail.python.org/mailman/listinfo/python-list
