Just eyeballing this, Dmitry, I'm not convinced it would work if Wolfhart was sitting at a <foo> at the time he made his request, in which case the <foo> he was at would incorrectly be included.

Granted the original requirement is underspecified in this regard, so perhaps my observation is irrelevant. I'm not trying to nit-pick but I discounted the use of keys because of the arbitrary starting point for evaluation.

Wolfhart, am I being too pedantic here?