matching objects by a tuple field criterion

[bullockbefriending bard]

> There are certainly cases where the speedup is tremendous - think of a
> single integer in the first criteria - but then the overall performance
> depends on the real-live queries. If lot's of wildcards are used, you
> might end up slower if the tree-walk takes more time than the
> C-implemented list-iteration will cost you.

hopefully, won't need to do this then. i'll test the filter approach
tonight. generally speaking, going to be mostly wildcards most of the
time.