Em um mapa, se tenho presente um campo ::a, quero tornar obrigatório o campo ::b e ::c também obrigatórios?

campos dependentes.clj

(defn multi-answer [answer]
  (cond
    (or (contains? answer :answer/lat)
        (contains? answer :answer/lon)) :answer.type/text-with-location
    :else :answer.type/text))

(defmulti data-type multi-answer)

(s/def :answer/text (and string? #(<= (count %) 4096)))

(defmethod data-type :answer.type/text [_]
  (s/keys :req [:answer/text]))

(s/def :answer/lat double?)
(s/def :answer/lon double?)

(defmethod data-type :answer.type/text-with-location [_]
  (s/keys :req [:answer/text
                :answer/lat
                :answer/lon]))

(s/def :answer/data
  (s/multi-spec data-type multi-answer))

(s/explain-data :answer/data {:answer/text "42"})
(s/explain-data :answer/data {:answer/lat 0.0})
(s/explain-data :answer/data {:answer/lon 0.0})
(s/explain-data :answer/data {:answer/lat 0.0
                              :answer/lon 0.0})
(s/explain-data :answer/data {:answer/text "42"
                              :answer/lat  0.0})
(s/explain-data :answer/data {:answer/text "42"
                              :answer/lat  0.0
                              :answer/lon  0.0})