However, you're correct that none of this stuff helps at all with respect to "auto-vivication". And your code example does appear to help work around the problem when dealing with nested structures.

Hmm, Merlyn recently posted a snippet that walked a structure to it's leaf nodes, maybe we could combine the ideas of that snippet with this code to create a new form of exists?

-Scott

PS. the last paragraph was written "tongue-in-cheek", but it's late, and I would not be at all surprised to come into work on Monday to find someone actually wrote such a beast...