Reuse parse options for identical ctx and opts

Author: borkdude

src/sci/impl/interpreter.cljc

@@ -97,10 +97,9 @@
       #?@(:clj [utils/warn-on-reflection-var @utils/warn-on-reflection-var
                 utils/unchecked-math-var @utils/unchecked-math-var])}
      (let [reader (r/indexing-push-back-reader (r/string-push-back-reader s))
-           eval-string+? (when opts (:sci.impl/eval-string+ opts))
-           parse-opts (parser/parse-opts ctx nil)]
+           eval-string+? (when opts (:sci.impl/eval-string+ opts))]
        (loop [ret nil]
-         (let [expr (parser/parse-next* reader parse-opts)]
+         (let [expr (parser/parse-next ctx reader)]
            (if (utils/kw-identical? parser/eof expr)
              (if eval-string+?
                {:val ret

src/sci/impl/load.cljc

@@ -20,10 +20,9 @@
                :clj (instance? clojure.tools.reader.reader_types.IndexingReader reader)
                :cljs (implements? r/IndexingReader reader))
           reader
-          (r/indexing-push-back-reader reader))
-        parse-opts (parser/parse-opts ctx nil)]
+          (r/indexing-push-back-reader reader))]
     (loop [ret nil]
-      (let [x (parser/parse-next* reader parse-opts)]
+      (let [x (parser/parse-next ctx reader)]
         (if (utils/kw-identical? parser/eof x)
           ret
           (recur (utils/eval ctx x)))))))

src/sci/impl/parser.cljc

@@ -188,11 +188,23 @@
                                 :file @utils/current-file)
                          e)))))
 
+;; The last ctx and opts with their parse options, so callers that parse form
+;; by form with the same ctx and opts reuse them
+(def last-parse-opts (volatile! nil))
+
 (defn parse-next
   ([ctx r]
    (parse-next ctx r nil))
   ([ctx r opts]
-   (parse-next* r (parse-opts ctx opts))))
+   (let [cached @last-parse-opts
+         edamame-opts (if (and cached
+                               (identical? ctx (nth cached 0))
+                               (identical? opts (nth cached 1)))
+                        (nth cached 2)
+                        (let [edamame-opts (parse-opts ctx opts)]
+                          (vreset! last-parse-opts [ctx opts edamame-opts])
+                          edamame-opts))]
+     (parse-next* r edamame-opts))))
 
 (defn reader [x]
   (edamame/reader x))