change params-reset to backtrack in params-idx by number of needed params of its path, add test that verifies composability

src/clj/com/rpl/specter.cljx

@@ -132,15 +132,16 @@
 (defn params-reset [params-path]
   ;; TODO: error if not paramsneededpath
   (let [s (i/params-needed-selector params-path)
-        t (i/params-needed-transformer params-path)]
+        t (i/params-needed-transformer params-path)
+        needed (i/num-needed-params params-path)]
     (i/->ParamsNeededPath
       (i/->TransformFunctions
         i/RichPathExecutor
         (fn [params params-idx vals structure next-fn]
-          (s params 0 vals structure next-fn)
+          (s params (- params-idx needed) vals structure next-fn)
           )
         (fn [params params-idx vals structure next-fn]
-          (t params 0 vals structure next-fn)
+          (t params (- params-idx needed) vals structure next-fn)
           ))
       0)))
 
@@ -209,7 +210,7 @@
   (select* [this structure next-fn]
     (next-fn (set/intersection structure aset)))
   (transform* [this structure next-fn]
-    (let [subset  (set/intersection structure aset)
+    (let [subset (set/intersection structure aset)
           newset (next-fn subset)]
       (-> structure
           (set/difference subset)

test/com/rpl/specter/core_test.cljx

@@ -632,6 +632,11 @@
       (s/setval (map-key-walker :b) "X" {:a {:c {:b {:d 1}}}}))
   )
 
+(deftest recursive-params-composable-path-test
+  (let [p (s/comp-paths s/keypath map-key-walker)]
+    (is (= [1] (s/select (p 1 :a) [{:a 3} {:a 1} {:a 2}])))
+    ))
+
 (deftest all-map-test
   (is (= {3 3} (s/transform [s/ALL s/FIRST] inc {2 3})))
   (is (= {3 21 4 31} (s/transform [s/ALL s/ALL] inc {2 20 3 30})))