If I had my way

[Andrei Alexandrescu]

On 12/11/11 12:17 PM, Chad J wrote:
> On 12/11/2011 11:21 AM, Andrei Alexandrescu wrote:
>> On 12/11/11 9:14 AM, Chad J wrote:
>>>
>>> I think one thing that could would be (optional) reference counting for
>>> transitively atomic types.  Of course, this is just another kind of
>>> garbage collection, but it is /deterministic/ and parallelizes well, and
>>> I bet this would open up a large amount of Phobos while the
>>> stop-the-world collector is offline, and with little or no code change.
>>
>> I think the language has enough (in theory) and nearly enough (in
>> practice) expressiveness to implement reference counted classes in a
>> library, virtually transparently. I mean one could define a template
>> RefCounted (an extended version of what's now in std) such that this
>> pattern is possible:
>>
>> // client code
>> class WidgetImpl {
>>    ...
>> }
>>
>> alias RefCounted!WidgetImpl Widget;
>>
>> Aside from using WidgetImpl in type relationships, using Widget would
>> transparently insert the appropriate reference counting without
>> otherwise interfering with normal WidgetImpl semantics.
>>
>>
>> Andrei
>
> This is good.  So stick it in the runtime and make the compiler emit
> RefCounted!___ templates whenever it finds a transitively atomic type.
>
> This can be done alongside the existing garbage collector.
>
> Then we can benchmark different combinations of memory management
> strategies.
>
> Two compiler flags can work in tandem:
> -nogc
> -norefcount
>
> (Turn them both off if you really want to break Phobos.)

We considered that route, and concluded it's marred by too many issues.

Andrei