AA default value?

[Janice Caron]

On 1/25/08, Janice Caron <caron800 at googlemail.com> wrote:
>     ((p = (key in aa)) is null) ? *p : defaultValue)

Spot the deliberate (ahem) mistake! Hint - there's a missing
exclamation mark somewhere. :-)

Seriously, really I just want aa[key] to return some default value.
Whether that's value.init, or some settable property within AAs, or if
it could somehow be expressed at the call site - any or all of those
options would be fine.