use local def for cljs inline cache. faster and enables bootstrap compatibility

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

@@ -41,6 +41,8 @@
 (defn do-macroexpand-all [form]
   (riddley/macroexpand-all form))
 
+;;this is not a secure way to generate uuids – the `path` implementation
+;;for cljs uses an alternative strategy
 #+cljs
 (defn gen-uuid-str []
   (apply str (repeatedly 50 #(rand-int 9)))
@@ -723,12 +725,8 @@
    params-maker ; can be null
    ])
 
-(defonce PATH-CACHE
-  #+clj (java.util.concurrent.ConcurrentHashMap.)
-  ;;TODO: according to @dnolen, can forgo this for instead doing
-  ;;inline defs at runtime
-  #+cljs (atom {})
-  )
+#+clj
+(defonce PATH-CACHE (java.util.concurrent.ConcurrentHashMap.))
 
 (def MUST-CACHE-PATHS (mutable-cell false))
 
@@ -744,14 +742,6 @@
 (defn get-path-cache [^String k]
   (.get ^java.util.concurrent.ConcurrentHashMap PATH-CACHE k))
 
-#+cljs
-(defn add-path-cache! [k v]
-  (swap! PATH-CACHE (fn [m] (assoc m k v))))
-
-#+cljs
-(defn get-path-cache [k]
-  (get @PATH-CACHE k))
-
 (defn- extract-original-code [p]
   (cond
     (instance? LocalSym p) (:sym p)

src/clj/com/rpl/specter/macros.clj

@@ -414,7 +414,12 @@
       )))
 
 ;; still possible to mess this up with alter-var-root
-(defmacro path [& path] ; "inline cache"
+(defmacro path
+  "Same as calling comp-paths, except it caches the composition of the static part
+   of the path for later re-use (when possible). For almost all idiomatic uses
+   of Specter provides huge speedup. This macro is automatically used by the
+   select/transform/setval/replace-in/etc. macros."
+  [& path]
   (let [;;this is a hack, but the composition of &env is considered stable for cljs
         platform (if (contains? &env :locals) :cljs :clj)
         local-syms (if (= platform :cljs)
@@ -439,7 +444,18 @@
         ;; - with invokedynamic here, could go directly to the code
         ;; to invoke and/or parameterize the precompiled path without
         ;; a bunch of checks beforehand
-        cache-id (i/gen-uuid-str)
+        cache-id (i/gen-uuid-str) ;; used for clj
+        cache-sym (gensym "pathcache") ;; used for cljs
+        info-sym (gensym "info")
+
+        get-cache-code (if (= platform :clj)
+                         `(i/get-path-cache ~cache-id)
+                         cache-sym
+                         )
+        add-cache-code (if (= platform :clj)
+                         `(i/add-path-cache! ~cache-id ~info-sym)
+                         `(def ~cache-sym ~info-sym))
+
 
         precompiled-sym (gensym "precompiled")
         params-maker-sym (gensym "params-maker")
@@ -453,11 +469,14 @@
              ~(mapv (fn [p] `(fn [] ~p)) possible-params)
              ))
         ]
-    `(let [info# (i/get-path-cache ~cache-id)
+    `(let [;;TODO: for cljs, use the dynamic def strategy + exists for a direct
+           ;; inline cache
+
+           info# ~get-cache-code
            
            ^com.rpl.specter.impl.CachedPathInfo info#
             (if (nil? info#)
-              (let [info# (i/magic-precompilation
+              (let [~info-sym (i/magic-precompilation
                                ~prepared-path
                                ~(str *ns*)
                                (quote ~used-locals)
@@ -465,8 +484,8 @@
                                ;;as is used-locals in cljs...
                                (quote ~possible-params)
                                )]
-                (i/add-path-cache! ~cache-id info#)
-                info#
+                ~add-cache-code
+                ~info-sym
                 )
               info#
               )