Leaving aside the issues of detecting a query, I think it's a really bad idea to have the compiler force (badly guessed) semantic knowledge on me.
It's my code, I wrote it, and I don't want any compiler telling me that a query that caches previous results must be imperative! and not end in a ? .
I also thing needlessly polluting a namespace with addition symbols is a bad idea. You only get one namespace in arc, try to preserve it for the future.
