Operators used In locks:
& - means AND, @lock gate = key & passport means BOTH are necessary.
| - means OR, @lock gate = Key | Passport means one of them is enough.
! - means NOT, @lock gate = !gun means that you can't pass with a gun.
()- declare precedence, @lock Gate=(key|passport)&!gun
means a key, or a passport (or both) as long as there's no gun.
: - means MEMBER_OF, @lock gate = passport:+stamped_by_immigration
means that passport has to be a member of group +stamped_by_immigration.