On 12/03/2015 07:45 AM, Steven Schveighoffer wrote:
On 12/2/15 6:51 PM, Andrei Alexandrescu wrote:
On 12/02/2015 06:04 PM, ZombineDev wrote:
On Wednesday, 2 December 2015 at 19:39:47 UTC, Andrei Alexandrescu
wrote:
Once done, this is a fantastic example of (a) the power of generative
programming, and (b) the advantages of using library facilities
instead of built-in features.
https://issues.dlang.org/show_bug.cgi?id=15397
Who would want to take it?
Andrei
So, something like
http://dlang.org/phobos/std_bitmanip.html#.taggedPointer?
Sigh, yes. Both taggedPointer and taggedClassRef should be features of
bitfields, not distinct names. One good thing to do would be to
integrate those within bitfields, and then later perhaps undocumented.
taggedPointer and taggedClassRef are GC safe (despite the incorrect
warning listed in the docs). Your proposed mechanism is not.
It can be restricted to support what tagged* do.
IMO, we should keep those and close your enhancement, it doesn't add
anything useful. Seems to me something that can break very easily.
Please leave it open, thanks.
Phobos should in no way support such egregious casts implicitly. Even in
@system code.
Do you have any rationale to prefer arbitrary bitfield pointers over GC
safe ones?
1. The less restricted version offers use of high-order bits as well. If
we don't support that, those who need it will do that in client code
with the usual liabilities.
2. There's no reason for taggedPointer and taggedClassRef to exist. They
should be integrated within bitfields.
Andrei
