On Saturday, 21 October 2017 at 18:52:15 UTC, bitwise wrote:
On Wednesday, 18 October 2017 at 08:56:21 UTC, Satoshi wrote:
async/await (vibe.d is nice but useless in comparison to C# or
js async/await idiom)
Reference counting when we cannot use GC...
If I understand correctly, both of these depend on
implementation of 'scope' which is being worked on right now.
Scope is about preventing pointer escaping, ref-counting also
needs to make use-after-free safe which is currently in the early
spec phase.
Whether or not that is going to be a compile-time or runtime
check has yet to be figured out. If you have a great idea that we
should consider, let us know.
The recent IOPipe window invalidation discussion was a good
example of what such a mechanism would hopefully be able to
handle
(https://gist.github.com/MartinNowak/b406a6b7aa6d0964147c107771b64333#file-safety_dance-d-L43-L45).
I think reference counting needs 'scope' to be made safe. RC
also benefits from scope in that many of the
increments/decrements of the ref count can be elided. The
performance gain can be significant, and even more so when you
use atomic reference counting (like C++ shared_ptr) for thread
safety.
Well, there can be RC and shared(RC), only the latter would need
to do atomic ref-counting.
Async/Await needs to allocate state for the function's local
variables. When it's detected that the function's
state/enumerator won't escape it's current scope, it can be put
on the stack, which is a pretty big optimization.
We should figure out how to allocate RC/unique delegate contexts.
Not that with async/await you always escape the local context, as
it's the callback in the returned Promise/Task.
