added paramsfn helper macro for defining filter functions with later bound parameters

CHANGES.md

@@ -1,6 +1,7 @@
 ## 0.7.1 (unreleased)
 * view can now be late-bound parameterized
 * Added a late-bound parameterized version of using a function as a selector called "pred"
+* Added paramsfn helper macro for defining filter functions that take late-bound parameters
 
 ## 0.7.0
 * Added late-bound parameterization feauture: allows selectors that require params to be precompiled without the parameters, and the parameters are supplied later in bulk. This effectively enables Specter to be used in any situation with very high performance.

src/com/rpl/specter/macros.clj

@@ -107,6 +107,17 @@
     (paramspath* retrieve-params num-params impls)
     ))
 
+(defmacro paramsfn [params [structure-sym] & impl]
+  `(paramspath ~params
+     (~'select* [this# structure# next-fn#]
+       (let [afn# (fn [~structure-sym] ~@impl)]
+         (filter-select afn# structure# next-fn#)
+         ))
+     (~'transform* [this# structure# next-fn#]
+       (let [afn# (fn [~structure-sym] ~@impl)]
+         (filter-transform afn# structure# next-fn#)
+         ))))
+
 (defmacro paramscollector
   "Defines a Collector with late bound parameters. This collector can be precompiled
   with other selectors without knowing the parameters. When precompiled with other

test/com/rpl/specter/core_test.cljc

@@ -13,6 +13,7 @@
                        [cljs.test.check.generators :as gen]
                        [cljs.test.check.properties :as prop :include-macros true]]
                 )
+            [com.rpl.specter.macros :as m]
             [com.rpl.specter :as s]))
 
 ;;TODO:
@@ -523,6 +524,17 @@
             ))
         ))))
 
+(defspec paramsfn-test
+  (for-all+
+    [v (gen/vector (gen/elements (range 10)))
+     val (gen/elements (range 10))
+     op (gen/elements [inc dec])
+     comparator (gen/elements [= > <])]
+    (let [path (s/comp-paths s/ALL (m/paramsfn [p] [v] (comparator v p)))]
+      (= (s/transform (path val) op v)
+         (s/transform [s/ALL #(comparator % val)] op v)))
+      ))
+
 #?(:clj
 (deftest large-params-test
   (let [path (apply s/comp-paths (repeat 25 s/keypath))