d future or plans for d3

[Adam Wilson]

On Sun, 18 Dec 2011 15:02:17 -0800, Timon Gehr <timon.gehr at gmx.ch> wrote:

> On 12/18/2011 11:53 PM, Vladimir Panteleev wrote:
>> On Sunday, 18 December 2011 at 20:32:18 UTC, Andrei Alexandrescu wrote:
>>> That is an interesting opportunity. At any rate, I am 100% convinced
>>> precise GC is the only way to go, and I think I've convinced Walter to
>>> a good extent as well.
>>
>> Sacrificing something (performance, executable size) for something else
>> is not an unilateral improvement.
>
> It is an unilateral improvement if both options are kept open. I don't  
> see a reason to cease support for the current GC model.
>
> Furthermore, a generational GC performs much better than a simple  
> mark-sweep GC.

It seems to that we are really dancing around the potential solution. A  
pluggable GC interface that allowed the developer to choose the right GC  
for the task, or no GC at all. Imagine if all the developer had to do is  
set a compiler switch and the compiler automatically linked in the correct  
GC for the job. D could ship with a default GC then others could write  
different GC's based on different paradigms or their own needs. It would  
be a piece of work to get the interfaces right, but definitely worth it in  
the long run.

Theoretically this would also give the developer the ability to link in  
multiple collectors and switch between them during program execution,  
provided the working set data was stored in a common format; although I  
have never heard of a use case for such a capability. I imagine that it  
could be useful if your application needs a low power state and you wanted  
to use a more power-efficient GC over a more precise one. I'm just  
theorizing here though. I'm sure their are technical snags that would  
prevent this from happening.

I think supporting a NoGC environment is a good idea in the long run as  
their are cases to be made for manual memory management, but it also  
shouldn't be our first goal. GC's are were the value is.

-- 
Adam Wilson
Project Coordinator
The Horizon Project
http://www.thehorizonproject.org/