CLJS-2374: Print js/Infinity, js/-Infinity, js/NaN using new reader literals

Author: mfikes

benchmark/cljs/benchmark_runner.cljs

@@ -407,4 +407,12 @@
 (simple-benchmark [] (str "1") 1000000)
 (simple-benchmark [] (str "1" "2") 1000000)
 (simple-benchmark [] (str "1" "2" "3") 1000000)
+
+(println ";; printing of numbers and handling of ##Nan, ##Inf, ##-Inf")
+(simple-benchmark [x true] (pr-str x) 1000000)
+(simple-benchmark [x 10] (pr-str x) 1000000)
+(simple-benchmark [x js/NaN] (pr-str x) 1000000)
+(simple-benchmark [x js/Infinity] (pr-str x) 1000000)
+(simple-benchmark [x js/-Infinity] (pr-str x) 1000000)
+(simple-benchmark [x (js-obj)] (pr-str x) 1000000)
 (println)

src/main/cljs/cljs/core.cljs

@@ -9659,9 +9659,17 @@ reduces them without incurring seq initialization"
         (implements? IPrintWithWriter obj)
         (-pr-writer ^not-native obj writer opts)
 
-        (or (true? obj) (false? obj) (number? obj))
+        (or (true? obj) (false? obj))
         (-write writer (str obj))
 
+        (number? obj)
+        (-write writer
+          (cond
+            ^boolean (js/isNaN obj) "##NaN"
+            (identical? obj js/Number.POSITIVE_INFINITY) "##Inf"
+            (identical? obj js/Number.NEGATIVE_INFINITY) "##-Inf"
+            :else (str obj)))
+
         (object? obj)
         (do
           (-write writer "#js ")

src/test/cljs/cljs/core_test.cljs

@@ -1472,6 +1472,11 @@
   (let [a (atom :usual-value)]
     (is (= :usual-value (reset! a (first (reset-vals! a :almost-never-seen-value)))))))
 
+(deftest test-cljs-2374
+  (is (= "##NaN" (pr-str js/NaN)))
+  (is (= "##Inf" (pr-str js/Infinity)))
+  (is (= "##-Inf" (pr-str js/-Infinity))))
+
 (comment
   ;; ObjMap
   ;; (let [ks (map (partial str "foo") (range 500))