BigInt -- a challenge for std.allocator

[Joseph Rushton Wakeling]

On 29/10/13 15:58, Dmitry Olshansky wrote:
> Can't it use ref-counted COW? Then since there is only 1 reference to the
> original block it may mutate it in-place else it creates new chunk with refs=1
> and decrements the original count. Maybe I'm missing something but it shouldn't
> be that hard.

Yes, that's pretty much what I was thinking of.  The question is how to 
implement it in terms of std.allocator -- or is that the wrong base to build 
ref=counted memory upon?