poor-mans-conformer.cljs

(def reg
  {::doc       '(keys [::id ::title ::summary ::authors])
   ::doc2      '(keys [::title])
   ::title     :field/text
   ::summary   :field/text
   ::authors   '(and (coll-of ::author) :field/many)
   ::author    '(keys [::id ::name])
   :field/text (fn [data] {:value data :type :text})
   :field/many (fn [data] {:value data :type :many})})

(declare conform)

(defn conform-key
  [data k]
  (println :conform-key data k)
  (let [simple-k (keyword (name k))]
    (assert (contains? data simple-k) (str "Expected" simple-k " in " (keys data)))
    (update data simple-k conform k)))

(defn conform
  [data spec]
  (let [c (get reg spec)]
    (cond
      (keyword? c) (conform data c)
      (seq? c) (let [[a b] c]
                 (println :a a :b b)
                 (cond
                   (= a 'keys) (reduce conform-key data b)
                   (= a 'coll-of) (do (assert (coll? data) (str "Expected a collection, got " (pr-str data)))
                                      (map #(conform % b) data))
                   (= a 'and) (reduce conform data (rest c))))
      (ifn? c) (c data)
      :else data)))