On Wednesday, 7 October 2015 at 10:03:44 UTC, Namespace wrote:
On Wednesday, 7 October 2015 at 09:49:27 UTC, Marc Schütz wrote:
Really, I don't get why everyone wants to have builtin
refcounting, when all that's required is a working way to make
escape-proof references.
Because there is no guarantee that others, who use your code,
get it right and use those constructs.
Language-supported ref-counting wouldn't fix that. As long as
you're allowed to put a ref-counted object inside of a GC-managed
object, it's possible that the GC will ultimately managed the
lifetime of your ref-counted object - or even that it will never
be destroyed, because it simply isn't collected prior to the
program shutting down. And it's not like we're going to make it
illegal to put a ref-counted object inside of a GC-managed
object. That would be needlessly restrictive. Ultimately,
programmers simply have to be smart about what they do with
objects on the GC heap if deterministic destruction is required.
Having ref-counting built into the language will allow us to make
it more efficient and provide some safety guarantees that can't
necessarily be provided in a struct, but it doesn't make it so
that no one can misuse ref-counted objects.
Ultimately, the largest benefit to having ref-counting built into
the language will probably be that we can the have exceptions be
reference counted - and maybe even make it so that they're
malloced normally so that they can be used in @nogc code. Most of
the benefits of ref-counting can already be done with structs.
- Jonathan M Davis
