add in transients namespace

src/clj/com/rpl/specter/transients.cljx

@@ -0,0 +1,91 @@
+(ns com.rpl.specter.transients
+  #+cljs
+  (:require-macros [com.rpl.specter.macros
+                    :refer
+                    [defnav
+                     defpathedfn]])
+  (:use #+clj
+        [com.rpl.specter.macros :only
+         [defnav
+          defpathedfn]])
+  (:require [com.rpl.specter.impl :as i]
+            [com.rpl.specter :refer [subselect selected?]]))
+
+(defnav
+  ^{:doc "Navigates to the specified key of a transient collection,
+          navigating to nil if it doesn't exist."}
+  keypath!
+  [key]
+  (select* [this structure next-fn]
+    (next-fn (get structure key)))
+  (transform* [this structure next-fn]
+    (assoc! structure key (next-fn (get structure key)))))
+
+(def END!
+  "Navigates to an empty (persistent) vector at the end of a transient vector."
+  (i/comp-paths* (i/->TransientEndNavigator)))
+
+(defn- t-get-first
+  [tv]
+  (nth tv 0))
+
+(defn- t-get-last
+  [tv]
+  (nth tv (dec (i/transient-vec-count tv))))
+
+(defn- t-update-first
+  [tv next-fn]
+  (assoc! tv 0 (next-fn (nth tv 0))))
+
+(defn- t-update-last
+  [tv next-fn]
+  (let [i (dec (i/transient-vec-count tv))]
+    (assoc! tv i (next-fn (nth tv i)))))
+
+(def FIRST!
+  "Navigates to the first element of a transient vector."
+  (i/->PosNavigator t-get-first t-update-first))
+
+(def LAST!
+  "Navigates to the last element of a transient vector."
+  (i/->PosNavigator t-get-last t-update-last))
+
+#+clj
+(defn- select-keys-from-transient-map
+  "Selects keys from transient map, because built-in select-keys uses
+  `find` which is unsupported."
+  [m m-keys]
+  (loop [result {}
+         m-keys m-keys]
+    (if-not (seq m-keys)
+      result
+      (let [k (first m-keys)
+            ;; support Clojure 1.6 where contains? is broken on transients
+            item (get m k ::not-found)]
+        (recur (if-not (identical? item ::not-found)
+                 (assoc result k item)
+                 result)
+               (rest m-keys))))))
+
+#+cljs
+(defn- select-keys-from-transient-map
+  "Uses select-keys on a transient map."
+  [m m-keys]
+  (select-keys m m-keys))
+
+(defnav
+  ^{:doc "Navigates to the specified persistent submap of a transient map."}
+  submap!
+  [m-keys]
+  (select* [this structure next-fn]
+    (next-fn (select-keys-from-transient-map structure m-keys)))
+  (transform* [this structure next-fn]
+    (let [selected (select-keys-from-transient-map structure m-keys)
+          res (next-fn selected)]
+      (as-> structure %
+        (reduce (fn [m k]
+                  (dissoc! m k))
+                % m-keys)
+        (reduce-kv (fn [m k v]
+                     (assoc! m k v))
+                   % res)))))