std.allocator ready for some abuse

[Vladimir Panteleev]

On Thursday, 24 October 2013 at 19:53:56 UTC, Andrei Alexandrescu 
wrote:
> I know it's been a long wait. Hopefully it was worth it. The 
> alpha release of untyped allocators is ready for tire-kicking 
> and a test drive.

Very, very nice!

One question that immediately jumps out for me:

As a primitive, will deallocateAll always call the parent's 
deallocate/deallocateAll?

Sometimes it's useful to tell a top-level allocator to forget it 
allocated anything, but not actually free memory, so that it can 
be reused - similarly to Appender's clear method. There doesn't 
seem to be an easy way to do it with Freelist, as it will always 
forward to the parent's deallocate or deallocateAll. Perhaps 
there could be a "clear" primitive too?

Spied two typos:
- s/AllocatorWithOptions/AllocatorWithStats/
- s/an the call/the call/