Unlike Casbah and Korma, we already use query language data structures as close to what MongoDB uses as possible
(Clojure maps, vectors, numerics and strings are effectively JSON) so we don't need any layers on top, they won't improve
anything.
Having these operators is nice beacuse if you use atomic operators a lot, this will make sure Clojure compiler catches
typos for you. It is completely opt-in, however.
Finally, having a function inserted carries certain runtime performance cost and having $operator macros
that evaluate to themselves does not.
Per discussion with Alex.
c109702117