implementors of IFn now get direct invoke implementations, add (vector

0) benchmark, ~2X faster under V8.

benchmark/cljs/benchmark_runner.cljs

@@ -56,6 +56,7 @@
 (simple-benchmark [coll [1 2 3]] (nth coll 0) 1000000)
 (simple-benchmark [coll [1 2 3]] (-nth coll 0) 1000000)
 (simple-benchmark [coll [1 2 3]] (-nth ^not-native coll 0) 1000000)
+(simple-benchmark [coll [1 2 3]] (coll 0) 1000000)
 (simple-benchmark [coll [1 2 3]] (conj coll 4) 1000000)
 (simple-benchmark [coll [1 2 3]] (-conj coll 4) 1000000)
 (simple-benchmark [coll [1 2 3]] (seq coll) 1000000)

src/clj/cljs/core.clj

@@ -658,6 +658,12 @@
          (let [~this ~self-sym]
            ~@body)))))
 
+;; for IFn invoke implementations, we need to drop first arg
+(defn adapt-ifn-invoke-params [type [[this & args :as sig] & body]]
+  `(~(vec args)
+     (this-as ~(vary-meta this assoc :tag type)
+       ~@body)))
+
 (defn adapt-proto-params [type [[this & args :as sig] & body]]
   `(~(vec (cons (vary-meta this assoc :tag type) args))
      (this-as ~this
@@ -669,18 +675,30 @@
             ~(with-meta `(fn ~@(map #(adapt-obj-params type %) meths)) (meta form))))
     sigs))
 
+(defn ifn-invoke-methods [type-sym meths]
+  (map
+    (fn [meth]
+      (let [arity (count (first meth))]
+        `(set! ~(prototype-prefix type-sym
+                  (symbol (core/str "cljs$core$IFn$_invoke$arity$" arity)))
+           (fn ~meth))))
+    meths))
+
 (defn add-ifn-methods [type type-sym [f & meths :as form]]
-  (let [meths    (map #(adapt-ifn-params type %) meths)
+  (let [meths'   (map #(adapt-ifn-params type %) meths)
         this-sym (with-meta 'self__ {:tag type})
         argsym   (gensym "args")]
-    [`(set! ~(prototype-prefix type-sym 'call) ~(with-meta `(fn ~@meths) (meta form)))
-     `(set! ~(prototype-prefix type-sym 'apply)
-        ~(with-meta
-           `(fn ~[this-sym argsym]
-              (this-as ~this-sym
-                (.apply (.-call ~this-sym) ~this-sym
-                  (.concat (array ~this-sym) (aclone ~argsym)))))
-           (meta form)))]))
+    (concat
+      [`(set! ~(prototype-prefix type-sym 'call) ~(with-meta `(fn ~@meths') (meta form)))
+       `(set! ~(prototype-prefix type-sym 'apply)
+          ~(with-meta
+             `(fn ~[this-sym argsym]
+                (this-as ~this-sym
+                  (.apply (.-call ~this-sym) ~this-sym
+                    (.concat (array ~this-sym) (aclone ~argsym)))))
+             (meta form)))]
+      (ifn-invoke-methods type-sym
+        (map #(adapt-ifn-invoke-params type %) meths)))))
 
 (defn add-proto-methods* [pprefix type type-sym [f & meths :as form]]
   (let [pf (core/str pprefix f)]