atom

(atom v)

Wraps v in a cell every state verb reads and writes; (deref a) and @a read it, the reader form the same operation. The verb set is deref/swap!/reset!/compare-and-set!; every one answers the new value and works as a function value, so (map deref atoms) runs. Misuse of a non-atom signals. There is no add-watch/remove-watch: watches are refused by name.