GC/non-GC memory as part of data type?

[jmh530]

On Wednesday, 13 November 2019 at 15:19:38 UTC, Gregor Mückl 
wrote:
> Hi!
>
> This is an attempt to follow up on the DIP1025 discussion: what 
> happens if all pointers/arrays/references carry the origin of 
> the pointed to memory region as part of their type? The goal is 
> to have a cleaner, more explicit separation of GC and non-GC 
> heaps.
> [snip]

I'm sure there's a lot that I haven't considered, but it seems 
like that should be possible just that you might have to write up 
some of your own functionality. You could do something like below 
and then write some different versions of malloc, etc, and GC 
allocation functions and anything that uses the GC (like dynamic 
arrays), and probably your own ref too.

import std.traits : isPointer;

enum AllocStrategy
{
     GC,
     malloc,
     other
}

struct Ptr(T, AllocStrategy allocStrategy)
     if (isPointer!T)
{
     T x;
     alias x this;
}

void main() {
     int x = 1;
     auto y = Ptr!(int*, AllocStrategy.GC)(new int(x));
     assert(*y == 1);
}