[:] as empty associative array literal, plus warning for null

[Jonathan M Davis]

On Wednesday, July 03, 2013 22:00:39 Andrei Alexandrescu wrote:
> > A lot less arbitrary than having to initialize AAs into an empty state
> > by adding and removing a mapping.
> 
> Could be a function call. I find it unnecessary to just add new notation
> for every single little thing.

True, but we should probably at least add something to the AA implementation 
to do this, since a function at that level can create an AA that's empty 
without having to add and remove an element. And actually, I might as well 
open an enhancement request for that:

http://d.puremagic.com/issues/show_bug.cgi?id=10535

- Jonathan M Davis