Hi all, I am writing an application whose main purpose is data storage (it's a computerised log book). It stores its data as yaml. I need some way of keeping a collection of objects that are "sanctioned" (in the log book) so I can search them, calculate statistics on them, write them to disk and so on. I've done some hunting around for a pattern which fits this, and I can't see one that fits my problem (which would seem to be a fairly common one). I don't want to just search ObjectSpace, because that would turn up half-formed not-yet-"sanctioned" objects. Can anyone suggest one or more possible ways I might approach such a problem? The obvious way seems to be to create an XyzStore class (probably inheriting from a builtin data structure) which carries extra methods to do whatever aggregate calculations I want, but I do wonder if there's a better solution that I am missing, not being terribly versed in programming patterns. Tim. -- Tim Bates tim / bates.id.au