cljrs-stdlib 0.1.51

Built-in standard library namespaces for clojurust (clojure.string, clojure.set, clojure.test, …)
Documentation 
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;; clojure.data — recursive comparison of Clojure data structures.
(ns clojure.data
  (:require [clojure.set :as set]))

(defn equality-partition
  "Returns the equality partition for x: :atom, :set, :sequential, or :map."
  [x]
  (cond
    (nil? x)        :atom
    (map? x)        :map
    (set? x)        :set
    (sequential? x) :sequential
    :else           :atom))

(defn atom-diff
  "Diff for atomic (non-collection) values."
  [a b]
  (if (= a b) [nil nil a] [a b nil]))

(defn vectorize
  "Convert an associative-by-numeric-index collection to a vector,
  filling nil for missing indices."
  [m]
  (when (seq m)
    (reduce (fn [result [k v]]
              (assoc result k v))
            (vec (repeat (apply max (keys m)) nil))
            m)))

(defn diff-sequential
  "Diff two sequential collections."
  [a b]
  (let [a-len (count a)
        b-len (count b)
        max-len (max a-len b-len)
        diffs (map (fn [i]
                     (diff (nth a i nil) (nth b i nil)))
                   (range max-len))
        only-a (map first diffs)
        only-b (map second diffs)
        both   (map #(nth % 2) diffs)
        nnil?  (fn [s] (some #(not (nil? %)) s))]
    [(when (nnil? only-a) (vec only-a))
     (when (nnil? only-b) (vec only-b))
     (when (nnil? both)   (vec both))]))

(defn diff-set
  "Diff two sets."
  [a b]
  (let [only-a (set/difference a b)
        only-b (set/difference b a)
        both   (set/intersection a b)]
    [(not-empty only-a)
     (not-empty only-b)
     (not-empty both)]))

(defn diff-map
  "Diff two maps."
  [a b]
  (let [all-keys (set (concat (keys a) (keys b)))
        categorize (fn [k]
                     (let [in-a (contains? a k)
                           in-b (contains? b k)]
                       (cond
                         (and in-a in-b)
                         (let [[da db both] (diff (get a k) (get b k))]
                           [(when (not (nil? da)) [k da])
                            (when (not (nil? db)) [k db])
                            (when (not (nil? both)) [k both])])

                         in-a
                         [[k (get a k)] nil nil]

                         :else
                         [nil [k (get b k)] nil])))
        parts (map categorize all-keys)
        collect (fn [idx]
                  (let [entries (keep #(nth % idx) parts)]
                    (when (seq entries)
                      (into {} entries))))]
    [(collect 0)
     (collect 1)
     (collect 2)]))

(defn diff
  "Recursively computes the difference of a and b, returning a tuple of:
  [things-only-in-a things-only-in-b things-in-both]
  Each entry uses the appropriate collection type where possible."
  [a b]
  (if (= a b)
    [nil nil a]
    (let [part-a (equality-partition a)
          part-b (equality-partition b)]
      (if (= part-a part-b)
        (case part-a
          :atom       (atom-diff a b)
          :set        (diff-set a b)
          :sequential (diff-sequential a b)
          :map        (diff-map a b))
        (atom-diff a b)))))