Generators in D

[Sean Kelly]

On May 18, 2011, at 5:07 PM, Piotr Szturmaj wrote:

> Sean Kelly wrote:
>> 
>> On May 18, 2011, at 8:00 AM, Piotr Szturmaj wrote:
>> 
>>> Sean Kelly wrote:
>>>> On May 17, 2011, at 2:37 PM, Piotr Szturmaj wrote:
>>>>> 
>>>>> But couldn't Fiber's stack be scanned for references to itself and readjusted?
>>>> 
>>>> Without type information, there's no way to be sure that something is actually a reference, so corruption could occur.
>>> 
>>> Then, how GC scan Fiber's stack for references? I thought some portion of GC code could be used for this.
>> 
>> The GC is conservative.  If it encounters a value that matches the address of GCed memory, it won't collect the memory.
> 
> Ok. Maybe a requirement that cloneable fiber's function must be marked as @safe would work, as @safe functions can't take the address of a local variable or function parameter. Also asm and pointer arithmetic are prohibited. This way Fiber's stack can't have references to itself.
> 
> That should be enough to implement ForwardRange's save() for generators. Or still, I'm missing something I don't know yet :)

Referenced classes would still be shared between fibers.  I don't know if that would be an issue or not.