From 3dc7ad25ff473dcf83aea29c8b35e79c800294b2 Mon Sep 17 00:00:00 2001
From: Nathan Marz <nathan@nathanmarz.com>
Date: Fri, 10 Jun 2016 07:57:18 -0400
Subject: [PATCH] added collected? and DISPENSE navigators

---
 CHANGES.md                          |  2 ++
 src/clj/com/rpl/specter.cljx        |  5 ++++
 src/clj/com/rpl/specter/impl.cljx   | 30 ++++++++++++++++++++
 src/clj/com/rpl/specter/macros.clj  |  8 ++++++
 test/com/rpl/specter/core_test.cljx | 43 +++++++++++++++++++++++++++--
 5 files changed, 86 insertions(+), 2 deletions(-)

diff --git a/CHANGES.md b/CHANGES.md
index 3c2e044..343afbc 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -5,6 +5,8 @@
 * Added `selected-any?` operation that returns true if any element is navigated to.
 * Huge performance improvements to `select`, `select-one`, `select-first`, and `select-one!`
 * Added META navigator (thanks @aengelberg)
+* Added DISPENSE navigator to drop all collected values for subsequent navigation
+* Added `collected?` macro to create a filter function which operates on the collected values
 * Bug fix: END, BEGINNING, FIRST, and LAST now work properly on nil
 
 ## 0.11.2
diff --git a/src/clj/com/rpl/specter.cljx b/src/clj/com/rpl/specter.cljx
index 9d185ac..2368552 100644
--- a/src/clj/com/rpl/specter.cljx
+++ b/src/clj/com/rpl/specter.cljx
@@ -564,6 +564,11 @@
   (collect-val [this structure]
     val ))
 
+(def
+  ^{:doc "Drops all collected values for subsequent navigation."}
+  DISPENSE i/DISPENSE*)
+
+
 (defpathedfn if-path
   "Like cond-path, but with if semantics."
   ([cond-p then-path]
diff --git a/src/clj/com/rpl/specter/impl.cljx b/src/clj/com/rpl/specter/impl.cljx
index ffddf99..2bce1a1 100644
--- a/src/clj/com/rpl/specter/impl.cljx
+++ b/src/clj/com/rpl/specter/impl.cljx
@@ -609,6 +609,36 @@
         ret
         ))))
 
+
+(def collected?*
+  (->ParamsNeededPath
+    (->TransformFunctions
+      RichPathExecutor
+      (fn [params params-idx vals structure next-fn]
+        (let [afn (aget ^objects params params-idx)]
+          (if (afn vals)
+            (next-fn params (inc params-idx) vals structure)
+            NONE
+            )))
+      (fn [params params-idx vals structure next-fn]
+        (let [afn (aget ^objects params params-idx)]
+          (if (afn vals)
+            (next-fn params (inc params-idx) vals structure)
+            structure
+            ))))
+    1
+    ))
+
+(def DISPENSE*
+  (no-params-compiled-path
+    (->TransformFunctions
+      RichPathExecutor
+      (fn [params params-idx vals structure next-fn]
+        (next-fn params params-idx [] structure))
+      (fn [params params-idx vals structure next-fn]
+        (next-fn params params-idx [] structure))
+      )))
+
 (defn transform-fns-field [^CompiledPath path]
   (.-transform-fns path))
 
diff --git a/src/clj/com/rpl/specter/macros.clj b/src/clj/com/rpl/specter/macros.clj
index c87a29e..c5e5c49 100644
--- a/src/clj/com/rpl/specter/macros.clj
+++ b/src/clj/com/rpl/specter/macros.clj
@@ -611,3 +611,11 @@
   [apath transform-fn structure & args]
   `(i/compiled-replace-in* (path ~apath) ~transform-fn ~structure ~@args))
 
+(defmacro collected?
+  "Creates a filter function navigator that takes in all the collected values
+   as input. For arguments, can use `(collected? [a b] ...)` syntax to look
+   at each collected value as individual arguments, or `(collected? v ...)` syntax
+   to capture all the collected values as a single vector."
+  [params & body]
+  `(i/collected?* (fn [~params] ~@body))
+  )
diff --git a/test/com/rpl/specter/core_test.cljx b/test/com/rpl/specter/core_test.cljx
index a7e4916..666c190 100644
--- a/test/com/rpl/specter/core_test.cljx
+++ b/test/com/rpl/specter/core_test.cljx
@@ -8,7 +8,7 @@
              :refer [paramsfn defprotocolpath defnav extend-protocolpath
                      nav declarepath providepath select select-one select-one!
                      select-first transform setval replace-in defnavconstructor
-                     select-any selected-any?]])
+                     select-any selected-any? collected?]])
   (:use
     #+clj [clojure.test :only [deftest is]]
     #+clj [clojure.test.check.clojure-test :only [defspec]]
@@ -17,7 +17,7 @@
            :only [paramsfn defprotocolpath defnav extend-protocolpath
                   nav declarepath providepath select select-one select-one!
                   select-first transform setval replace-in defnavconstructor
-                  select-any selected-any?]]
+                  select-any selected-any? collected?]]
 
     )
 
@@ -1201,3 +1201,42 @@
   (is (empty? (select s/LAST nil)))
   (is (empty? (select s/ALL nil)))
   )
+
+(defspec dispense-test
+  (for-all+
+    [k1 gen/int
+     k2 gen/int
+     k3 gen/int
+     m (gen-map-with-keys gen/int gen/int k1 k2 k3)]
+    (= (select [(s/collect-one (s/keypath k1))
+                (s/collect-one (s/keypath k2))
+                s/DISPENSE
+                (s/collect-one (s/keypath k2))
+                (s/keypath k3)]
+               m)
+       (select [(s/collect-one (s/keypath k2))
+                (s/keypath k3)]
+               m)
+       )))
+
+(deftest collected?-test
+  (let [data {:active-id 1 :items [{:id 1 :name "a"} {:id 2 :name "b"}]}]
+    (is (= {:id 1 :name "a"}
+           (select-any [(s/collect-one :active-id)
+                        :items
+                        s/ALL
+                        (s/collect-one :id)
+                        (collected? [a i] (= a i))
+                        s/DISPENSE
+                        ]
+                        data)
+           (select-any [(s/collect-one :active-id)
+                        :items
+                        s/ALL
+                        (s/collect-one :id)
+                        (collected? v (apply = v))
+                        s/DISPENSE
+                        ]
+                        data)
+           ))
+    ))