Musicbrainz graph access examples

get-artist-names.clj

(defn get-track-artist-names
  ([track limit]
     (into {}
           (walk track
                 [[:out "artist_credit:track"]
                  [:in "artist_credit:artist_credit_name"]
                  [:out "artist:artist_credit_name" :id]
                  [:out "name:artist" "name"]]
                 limit))))

get-releases-freqs.clj

(defn get-track-releases-texts
  ([track limit]
     (frequencies
      (map first
           (walk track
                 [[:out "tracklist:track"]
                  [:in "tracklist:medium"]
                  [:out "release:medium"]
                  [:out "name:release" "name"]]
                 limit)))))

props.clj

(defn make-prefix
  ([id p ^"[B" r strings]
     (let [bb (java.nio.ByteBuffer/allocate (if r 9 5))]
       (.put bb (get-id-bytes id strings))
       (.put bb (byte (if (instance? Byte p) p (tag p))))
       (when r (.put bb r))
       (.array bb)))
  ([id p r]
     (make-prefix id p r nil))
  ([id p]
     (make-prefix id p nil nil)))

(defn accumulator
  ([f]
     (let [state (ref [])]
       (fn g
         ([] @state)
         ([x] (dosync (alter state conj x)) x)
         ([x & more] (g (apply f x more))))))
  ([]
     (accumulator identity)))

(defn get-props*
  ([^kyotocabinet.DB interned ^kyotocabinet.DB strings ^kyotocabinet.DB ids x]
     (let [acc (accumulator #(drop 2 (parse-interned ids %)))]
       (do-prefix acc interned (make-prefix x :prop nil strings))
       (acc))))