Pulling some builtin logic out

[Janice Caron]

On 31/03/2008, Kaja <kaja.fumei at gmail.com> wrote:
> Why couldn't a person use "in" on a user-defined AA?  According to the docs, its overloadable with opIn (but no example on the page so maybe its not supported anymore).

It's completely usable. I've used it.

But of course, you'd use opIn_r(), not opIn(), because it's "element
in container", not "container in element".