If you pick 1. and then want to evolve to 2. or 3., you might break existing applications using 1.

Yes, you're right; such a change may break existing queries in the future. It might be mitigated by supporting option 2. only after explicit enablement by the user. E.g. if the wish to make use of macros (should we ever support them) they'd have to turn this on. Then they'd know about this issue and could put proper escaping in place. That'd work for me. Emmanuel Bernard, Do you have any more thoughts on this?