container stuff

[bearophile]

Andrei Alexandrescu:
> Will look into it, sounds like an implementation matter.

Thinking a bit more about it, it's not just an implementation matter. If that suggestion of mine is accepted, then the foreach has to set and later reset one boolean value inside the data structure. So this boolean value if present must have a standard name, that has to be shown in that page about the standard API of the data structures :-)

Bye,
bearophile