REPL options merging needs to be more disciplined

eliminate :default-*. Instead first merge -repl-options, then original
options, then clojure.main style REPL options (with supplied
defaults).

Rhino error handling WIP. Default wrap-fn will not work as catching the
JS error will swallow the stacktrace.

Author: swannodette

src/clj/cljs/repl.clj

@@ -467,13 +467,13 @@
    form, evaluate the form and return the result. The result is always the value
    represented as a string."
   ([repl-env env form]
-    (eval-cljs repl-env env form nil))
+    (eval-cljs repl-env env form *repl-opts*))
   ([repl-env env form opts]
    (evaluate-form repl-env
      (assoc env :ns (ana/get-namespace ana/*cljs-ns*))
      "<cljs repl>"
      form
-     (wrap-fn form)
+     ((or (:wrap opts) wrap-fn) form)
      opts)))
 
 ;; Special REPL fns, these provide compatiblity with Clojure functions
@@ -620,7 +620,7 @@
       (.printStackTrace e))))
 
 (defn repl*
-  [repl-env {:keys [init need-prompt prompt flush read eval print caught reader print-no-newline source-map-inline]
+  [repl-env {:keys [init need-prompt prompt flush read eval print caught reader print-no-newline source-map-inline wrap]
              :or {init #()
                   need-prompt #(if (readers/indexing-reader? *in*)
                                  (== (readers/get-column-number *in*) 1)
@@ -643,20 +643,18 @@
         (merge
           {:cache-analysis true :source-map true}
           (cljsc/add-implicit-options
-            (assoc (merge (-repl-options repl-env) opts)
-              :init init
-              :need-prompt prompt
-              :flush flush
-              :read read
-              :print print
-              :caught caught
-              :reader reader
-              :print-no-newline print-no-newline
-              :source-map-inline source-map-inline
-              :output-dir (or (:output-dir opts)
-                              (:default-output-dir repl-env))
-              :target (or (:target opts)
-                          (:default-target repl-env)))))]
+            (merge-with (fn [a b] (if (nil? b) a b))
+              (-repl-options repl-env)
+              opts
+              {:init init
+               :need-prompt prompt
+               :flush flush
+               :read read
+               :print print
+               :caught caught
+               :reader reader
+               :print-no-newline print-no-newline
+               :source-map-inline source-map-inline})))]
     (env/with-compiler-env
      (or (::env/compiler repl-env) (env/default-compiler-env opts))
      (binding [ana/*cljs-ns* 'cljs.user

src/clj/cljs/repl/nashorn.clj

@@ -144,7 +144,8 @@
 
 (defrecord NashornEnv [engine debug]
   repl/IReplEnvOptions
-  (-repl-options [this] {})
+  (-repl-options [this]
+    {:output-dir ".cljs_nashorn_repl"})
   repl/IJavaScriptEnv
   (-setup [this {:keys [output-dir bootstrap output-to] :as opts}]
     (init-engine engine output-dir debug)
@@ -206,6 +207,6 @@
                 Use a minimal bootstrapped cljs.core environment if not specified."
   [& {:keys [debug] :as opts}]
   (let [engine (create-engine)]
-    (merge (NashornEnv. engine debug)
-      {:default-output-dir ".cljs_nashorn_repl"}
+    (merge
+      (NashornEnv. engine debug)
       opts)))

src/clj/cljs/repl/node.clj

@@ -169,6 +169,10 @@
                    (aget (.. js/goog -dependencies_ -nameToPath) name))))))))))
 
 (defrecord NodeEnv [host port socket proc]
+  repl/IReplEnvOptions
+  (-repl-options [this]
+    {:output-dir ".cljs_node_repl"
+     :target :nodejs})
   repl/IParseErrorMessage
   (-parse-error-message [_ _ _ _])
   repl/IJavaScriptEnv
@@ -188,9 +192,7 @@
           {:host "localhost"
            :port (+ 49000 (rand-int 10000))}
           options)]
-    (merge (NodeEnv. host port (atom nil) (atom nil))
-      {:default-output-dir ".cljs_node_repl"
-       :default-target :nodejs})))
+    (NodeEnv. host port (atom nil) (atom nil))))
 
 (defn repl-env
   [& {:as options}]

src/clj/cljs/repl/rhino.clj

@@ -69,12 +69,15 @@
 ;; =============================================================================
 
 (defn rhino-eval
-  [repl-env filename line js]
+  [{:keys [scope] :as repl-env} filename line js]
   (try
     (let [linenum (or line Integer/MIN_VALUE)]
       {:status :success
        :value (eval-result (-eval js repl-env filename linenum))})
     (catch Throwable ex
+      ;; manually set *e
+      ;; (ScriptableObject/putProperty scope "cljs.core._STAR_e"
+      ;;   (Context/javaToJS ex scope))
       {:status :exception
        :value (.toString ex)
        :stacktrace (stacktrace ex)})))
@@ -145,10 +148,27 @@
                (js/CLOSURE_IMPORT_SCRIPT
                  (aget (.. js/goog -dependencies_ -nameToPath) name)))))))))
 
+;; Catching errors and rethrowing in Rhino swallows the original trace
+;; https://groups.google.com/d/msg/mozilla.dev.tech.js-engine.rhino/inMyVKhPq6M/cY39hX20_z8J
+(defn wrap-fn [form]
+  (cond
+    (and (seq? form) (= 'ns (first form))) identity
+    ('#{*1 *2 *3 *e} form) (fn [x] `(cljs.core.pr-str ~x))
+    :else
+    (fn [x]
+      `(cljs.core.pr-str
+         (let [ret# ~x]
+           (set! *3 *2)
+           (set! *2 *1)
+           (set! *1 ret#)
+           ret#)))))
+
 (defrecord RhinoEnv []
   repl/IReplEnvOptions
   (-repl-options [this]
-    {:require-foreign true})
+    {:require-foreign true
+     :output-dir ".cljs_rhino_repl"
+     :wrap wrap-fn})
   repl/IJavaScriptEnv
   (-setup [this opts]
     (rhino-setup this opts))
@@ -167,8 +187,7 @@
     ;; Rhino is slow even with optimizations enabled
     (.setOptimizationLevel cx -1)
     (merge (RhinoEnv.)
-      {:default-output-dir ".cljs_rhino_repl"
-       :cx cx
+      {:cx cx
        :scope (.initStandardObjects cx)})))
 
 (comment