My Reference Safety System (DIP???)

Zach the Mystic via Digitalmars-d digitalmars-d at puremagic.com
Sun Mar 1 16:37:04 PST 2015


On Monday, 2 March 2015 at 00:06:52 UTC, deadalnix wrote:
> On Sunday, 1 March 2015 at 23:56:02 UTC, Zach the Mystic wrote:
>> On Sunday, 1 March 2015 at 14:40:54 UTC, Marc Sch├╝tz wrote:
>>> I don't think a callee-based solution can work:
>>>
>>>   class T {
>>>       void doSomething() scope;
>>>   }
>>>   struct S {
>>>       RC!T t;
>>>   }
>>>   void main() {
>>>       auto s = S(RC!T()); // `s.t`'s refcount is 1
>>>       T t = s.t;          // borrowing from the RC wrapper
>>>       foo(s);
>>>       t.doSomething();    // oops, `t` is gone
>>>   }
>>>   void foo(ref S s) {
>>>       s.t = RC!T();       // drops the old `s.t`
>>>   }
>>
>> I thought of this, and I disagree. The very fact of assigning 
>> to `T t` adds the reference count you need to keep `s.t` from 
>> disintegrating. As soon as you borrow, you increment the count.
>
> I'm sure many inc/dec can still be removed.

Do you agree or disagree with what I said? I can't tell.


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