No, of course not, I don't use symbolic references, sorry for confusion.

I have an array of messages, not a hash. The operation of converting that array to hash keyed by one of message properties (namely, uid) is exactly what I want to avoid as it is expensive.

I like your suggestion, though, of not having that message array in the first place, but I think this is hard to implement. At present the only format of getting those messages is in unordered lists, too bad (there's IMAP on the other end).