(ns potemkin.walk)

;; adapted from clojure.walk, but preserves metadata

(defn walk
  "Like `clojure.walk/walk`, but preserves metadata."
  [inner outer form]
  (let [x (cond
            (list? form) (outer (apply list (map inner form)))
            (instance? clojure.lang.IMapEntry form) (outer (vec (map inner form)))
            (seq? form) (outer (doall (map inner form)))
            (instance? clojure.lang.IRecord form)
              (outer (reduce (fn [r x] (conj r (inner x))) form form))
            (coll? form) (outer (into (empty form) (map inner form)))
            :else (outer form))]
    (if (instance? clojure.lang.IObj x)
      (with-meta x (merge (meta form) (meta x)))
      x)))

(defn postwalk
  "Like `clojure.walk/postwalk`, but preserves metadata."
  [f form]
  (walk (partial postwalk f) f form))

(defn prewalk
  "Like `clojure.walk/prewalk`, but preserves metadata."
  [f form]
  (walk (partial prewalk f) identity (f form)))