Switch values of two refs/atoms/agents

switch.clj

(defn switch-refs
  "Must be called in transaction"
  [a b]
  (let [av @a bv @b
        setter (fn [_ v] v)]
    (commute a setter bv)
    (commute b setter av)))

(defn switch!
  "Blocks on both sequentially, nontransactional"
  [a b]
  (let [av @a bv @b
        setter (fn [_ v] v)]
    (swap! a setter bv)
    (swap! b setter av)))

(defn switch-agents
  "Updates can happen in either order, and will be set to current value of a
   and b, not val at actual execution (=> should probably call after an await)"
  [a b]
  (let [av @a bv @b
        setter (fn [_ v] v)]
    (send a setter bv)
    (send b setter av)))