added cond-path and if-path selectors

src/clj/com/rpl/specter.clj

@@ -11,12 +11,8 @@
 
 ;; Selector functions
 
-(defn compiled-select
-  "Version of select that takes in a selector pre-compiled with comp-paths"
-  [^com.rpl.specter.impl.TransformFunctions tfns structure]
-  (let [^com.rpl.specter.impl.ExecutorFunctions ex (.executors tfns)]
-    ((.select-executor ex) (.selector tfns) structure)
-    ))
+(def ^{:doc "Version of select that takes in a selector pre-compiled with comp-paths"}
+  compiled-select compiled-select*)
 
 (defn select
   "Navigates to and returns a sequence of all the elements specified by the selector."
@@ -63,12 +59,9 @@
 
 ;; Update functions
 
-(defn compiled-update
-  "Version of update that takes in a selector pre-compiled with comp-paths"
-  [^com.rpl.specter.impl.TransformFunctions tfns update-fn structure]
-  (let [^com.rpl.specter.impl.ExecutorFunctions ex (.executors tfns)]
-    ((.update-executor ex) (.updater tfns) update-fn structure)
-    ))
+
+(def ^{:doc "Version of update that takes in a selector pre-compiled with comp-paths"}
+  compiled-update compiled-update*)
 
 (defn update
   "Navigates to each value specified by the selector and replaces it by the result of running
@@ -190,3 +183,22 @@
   (update [:a :b (putval 3)] + some-map)"
   [val]
   (->PutValCollector val))
+
+(defn cond-path
+  "Takes in alternating cond-fn selector cond-fn selector...
+   Tests the structure on the cond-fn, and if it matches uses the following selector for
+   the rest of the selector. Otherwise, it moves on to the next selector. If nothing
+   matches, then the structure is not selected."
+  [& conds]
+  (->> conds
+       (partition 2)
+       (map (fn [[c p]] [c (comp-paths* p)]))
+       doall
+       ->ConditionalPath
+       ))
+
+(defn if-path
+  "Like cond-path, but with if semantics."
+  ([cond-fn if-path] (cond-path cond-fn if-path))
+  ([cond-fn if-path else-path]
+    (cond-path cond-fn if-path (fn [_] true) else-path)))

src/clj/com/rpl/specter/impl.clj

@@ -469,3 +469,39 @@
   (update* [this structure next-fn]
     (next-fn structure)
     ))
+
+(defn compiled-select*
+  [^com.rpl.specter.impl.TransformFunctions tfns structure]
+  (let [^com.rpl.specter.impl.ExecutorFunctions ex (.executors tfns)]
+    ((.select-executor ex) (.selector tfns) structure)
+    ))
+
+(defn compiled-update*
+  [^com.rpl.specter.impl.TransformFunctions tfns update-fn structure]
+  (let [^com.rpl.specter.impl.ExecutorFunctions ex (.executors tfns)]
+    ((.update-executor ex) (.updater tfns) update-fn structure)
+    ))
+
+(deftype ConditionalPath [cond-pairs])
+
+(defn- retrieve-selector [cond-pairs structure]
+  (->> cond-pairs
+       (drop-while (fn [[c-fn _]] (not (c-fn structure))))
+       first
+       second
+       ))
+
+;;TODO: test nothing matches case
+(extend-protocol StructurePath
+  ConditionalPath
+  (select* [this structure next-fn]
+    (if-let [selector (retrieve-selector (.cond-pairs this) structure)]
+      (->> (compiled-select* selector structure)
+           (mapcat next-fn)
+           doall)))
+  (update* [this structure next-fn]
+    (if-let [selector (retrieve-selector (.cond-pairs this) structure)]
+      (compiled-update* selector next-fn structure)
+      structure
+      )))
+

test/clj/com/rpl/specter/core_test.clj

@@ -295,3 +295,23 @@
       (select [(comp-paths) k1 k2] m)
       (select [k1 (comp-paths) k2] m)
       )))
+
+(deftest cond-path-test
+  (is (= [4 2 6 8 10]
+         (select [ALL (cond-path even? [(view inc) (view inc)]
+                                 #(= 3 %) (view dec))]
+                 [1 2 3 4 5 6 7 8])))
+  (is (empty? (select (if-path odd? (view inc)) 2)))
+  (is (= [6 2 10 6 14] 
+         (update [(putval 2)
+                  ALL
+                  (if-path odd? [(view inc) (view inc)] (view dec))]
+                  *
+                  [1 2 3 4 5]
+                     )))
+  (is (= 2
+         (update [(putval 2)
+                  (if-path odd? (view inc))]
+                  *
+                  2)))
+  )