On Friday, 20 October 2017 at 20:05:51 UTC, jmh530 wrote:
Interesting proposals, but IMHO, the only ESSENTIAL feature
missing in D is the possibility to program in D using a
built-in reference-counting based variant of the standard
library.
Look at the goals for H2 2017
https://wiki.dlang.org/Vision/2017H2
The top three things: 1) @safety, 2) @nogc, 3) betterC. Under
#2, it specifically says safe reference counting. It's getting
worked on...
Yes, it's being worked on, but it's also a huge topic to come up
with @safe memory management approach. It's literally about
eradicating one of the biggest security bug classes,
use-after-free.
Currently I'm working towards an ORM library starting at I/O
(https://github.com/MartinNowak/io) to better inform the
necessary design.
We already found couple of interesting litmus tests, like the
window in iopipe.
auto window = iopipe.window;
iopipe.extend(512); // invalidates window :/
window[0]; // use after-free
Another thing that Walter previously found out is that exceptions
are a major hassle for @nogc. I don't like the RC Exception
solution much though, as it's a fairly specific workaround
(https://github.com/dlang/druntime/pull/1804).
Towards that goal, making exception nesting optional and
providing access to the current Exception in flight would allow
to use the staticError approach in most places.
https://github.com/dlang/druntime/blob/bc832b18430ce1c85bf2dded07bbcfe348ff0813/src/core/exception.d#L683
Recently I wondered why we cannot semantically transform
exceptions to the equivalent of function calls.
- throw Uniq!Exception; // ctor, some struct that's implicitly
convertible to a Throwable
- catch (scope Exception e) // handler 1
{
throw e; // basically continue to unwind
}
- catch (scope Exception e) {} // handler 2
- done unwinding, destroy thrown value
We still support gotos in catch handlers, but should be possible
to call destructors in catch handlers anyhow.
https://github.com/dlang/druntime/pull/1804/files#diff-f3953348bb302c27a8cea926c62c02e6R69
