added not-selected? and transformed selectors

src/com/rpl/specter.cljc

@@ -148,6 +148,19 @@
            empty?
            not))))
 
+(defn not-selected? [& path]
+  (complement (selected? (comp-paths* path))))
+
+(defn transformed
+  "Navigates to a view of the current value by transforming it with the
+   specified selector and update-fn."
+  [selector update-fn]
+  (let [compiled (comp-paths* selector)]
+    (view
+      (fn [elem]
+        (compiled-transform compiled update-fn elem)
+        ))))
+
 (extend-type #?(:clj clojure.lang.Keyword :cljs cljs.core/Keyword)
   StructurePath
   (select* [kw structure next-fn]

test/com/rpl/specter/core_test.cljc

@@ -395,3 +395,12 @@
   (is (= nil (s/select-one! s/ALL [nil])))
   (is (thrown? #?(:clj Exception :cljs js/Error) (s/select-one! s/ALL [])))
   )
+
+(defspec transformed-test
+  (for-all+
+    [v (gen/vector gen/int)
+     pred (gen/elements [even? odd?]
+     op   (gen/elements [inc dec]))]
+    (= (select-one (transformed [ALL pred] op) v)
+       (transform [ALL pred] op v))
+    ))