Fiber local GC

[Ola Fosheim Grøstad via Digitalmars-d]

On Saturday, 25 June 2016 at 12:01:25 UTC, rikki cattermole wrote:
>> 2. You can hand out borrowed fiber-references to the fiber 
>> heap when
>> calling non-fiber functions, but fiber-references can never be 
>> turned
>> into non-fiber references.
>
> This worries me.
>
> 1. This adds ref counting or some other form of restriction 
> which has not been declared as to what it is.

You can get quite far using modern type systems and static 
analysis. You don't need to reference count, unless you export 
the object outside the fiber. Or rather, the reference count is 
only increased outside the fiber, if it is not reference outside 
the fiber it stays at 0 (conceptually).

> 2. Removes the ability to assign to globals limiting usage.

You can add weak-references. Pin the object as being weakly 
referenced. When the weak reference is accessed (using RAII), and 
the object is alive, a weak-reference-counter is increased, when 
the access is over (RAII goes out of scope) the 
weak-reference-counter is decreased. If the object no longer 
exists you get either null or an exception.