ref semantics with hashes

[Jonathan M Davis]

On Wednesday, May 02, 2012 13:32:04 H. S. Teoh wrote:
> On Wed, May 02, 2012 at 09:38:35PM +0200, Andrej Mitrovic wrote:
> [...]
> 
> > So if the hash wasn't already initialized then the reference in the
> > Foo struct is a reference to null, and if you duplicate that reference
> > and add a key the old reference still points to null.
> > 
> > The only way to ensure a proper link with a hash is to initialize it
> > with a key and then immediately remove that key, which makes the hash
> 
> > not-null but empty:
> [...]
> 
> > Why do we have such error-prone semantics?
> 
> I was told that this was expected behaviour.
> 
> Should the new AA implementation change this, so that it always
> allocates an empty AA upon instantiation?

The way that AAs work in this regard is identical to how dynamic arrays work.

- Jonathan M Davis