A case for valueless AA's?

[David Nadlinger]

On 3/30/11 5:02 AM, dsimcha wrote:
> […] Furthermore, most programs will probably want a hash set.

First of all, I agree that we really want to have a hash set in Phobos. 
I think that a first implementation wouldn't even need to support 
advanced operations like union, intersection, etc., but we should really 
have some kind of set in the standard library which doesn't look plain 
ugly (recently, I quickly needed some set implementation and abused AAs 
for it, but this isn't a serious option).

I vaguely remember you having an optimized AA library, David. Does it 
contain something of interest for a pure set implementation as well, or 
is it strictly tailored towards hash maps?

David