CLJS-3375: Bridge tools.reader (#178)

* add cljs.vendor.bridge file to bridge tools.reader and vendorized tools.reader
* return clojure.tools.reader/*alias-map* first
* only auto-bridge when invoking the REPL

Author: swannodette

Diff for: pom.template.xml

@@ -278,7 +278,7 @@
                         <configuration>
                             <cleanAOTNamespaces>true</cleanAOTNamespaces>
                             <namespaces>
-                                <namespace>!clojure.tools.reader.*</namespace>
+                                <namespace>!cljs.vendor.bridge</namespace>
                             </namespaces>
                         </configuration>
                     </execution>

Diff for: src/main/clojure/cljs/analyzer.cljc

@@ -4395,6 +4395,14 @@
     ((juxt :requires :require-macros :as-aliases)
      (get-namespace ns))))
 
+(defn get-bridged-alias-map
+  "Returns clojure.tools.reader/*alias-map* for bridging"
+  []
+  (try
+    @(ns-resolve 'clojure.tools.reader '*alias-map*)
+    (catch Throwable t
+      nil)))
+
 #?(:clj
    (defn forms-seq*
      "Seq of Clojure/ClojureScript forms from rdr, a java.io.Reader. Optionally
@@ -4795,7 +4803,7 @@
                          *unchecked-arrays* false])
                *cljs-ns* 'cljs.user
                *cljs-file* nil
-               reader/*alias-map* (or reader/*alias-map* {})]
+               reader/*alias-map* (or (get-bridged-alias-map) reader/*alias-map* {})]
        (loop [ns nil forms forms last-ast nil]
          (if (some? forms)
            (let [form (first forms)
@@ -4853,7 +4861,7 @@
                 (if (or skip-cache (not cache) (requires-analysis? res cache output-dir opts))
                   (binding [*cljs-ns* 'cljs.user
                             *cljs-file* path
-                            reader/*alias-map* (or reader/*alias-map* {})]
+                            reader/*alias-map* (or (get-bridged-alias-map) reader/*alias-map* {})]
                     (when (or *verbose* (:verbose opts))
                       (util/debug-prn "Analyzing" (str res)))
                     (let [env (assoc (empty-env) :build-options opts)

Diff for: src/main/clojure/cljs/compiler.cljc

@@ -1559,7 +1559,7 @@
        (binding [*out*                 out
                  ana/*cljs-ns*         'cljs.user
                  ana/*cljs-file*       (.getPath ^File src)
-                 reader/*alias-map*    (or reader/*alias-map* {})
+                 reader/*alias-map*    (or (ana/get-bridged-alias-map) reader/*alias-map* {})
                  ana/*checked-arrays*  (or ana/*checked-arrays* (:checked-arrays opts))
                  ana/*cljs-static-fns* (or ana/*cljs-static-fns* (:static-fns opts))
                  *source-map-data*     (when (:source-map opts)

Diff for: src/main/clojure/cljs/repl.cljc

@@ -1054,6 +1054,10 @@
                                   [cljs.pprint :refer [pprint] :refer-macros [pp]]]
                   bind-err true}
              :as opts}]
+  ;; bridge clojure.tools.reader to satisfy the old contract
+  (when (and (find-ns 'clojure.tools.reader)
+             (not (find-ns 'cljs.vendor.bridge)))
+    (clojure.core/load "vendor/bridge"))
   (doseq [[unknown-opt suggested-opt] (util/unknown-opts (set (keys opts)) (set/union known-repl-opts cljsc/known-opts))]
     (when suggested-opt
       (println (str "WARNING: Unknown option '" unknown-opt "'. Did you mean '" suggested-opt "'?"))))

Diff for: src/main/clojure/cljs/vendor/bridge.clj

@@ -0,0 +1,42 @@
+;   Copyright (c) Rich Hickey. All rights reserved.
+;   The use and distribution terms for this software are covered by the
+;   Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
+;   which can be found in the file epl-v10.html at the root of this distribution.
+;   By using this software in any fashion, you are agreeing to be bound by
+;   the terms of this license.
+;   You must not remove this notice, or any other, from this software.
+
+(ns cljs.vendor.bridge
+  (:require [cljs.vendor.clojure.tools.reader.reader-types :as vendor]
+            [clojure.tools.reader.reader-types :as readers]))
+
+(extend-protocol vendor/Reader
+  clojure.tools.reader.reader_types.Reader
+  (read-char [reader]
+    (readers/read-char reader))
+  (peek-char [reader]
+    (readers/peek-char reader)))
+
+(extend-protocol vendor/IPushbackReader
+  clojure.tools.reader.reader_types.IPushbackReader
+  (unread [reader ch]
+    (readers/unread reader ch)))
+
+(extend-protocol vendor/IndexingReader
+  clojure.tools.reader.reader_types.IndexingReader
+  (get-line-number [reader]
+    (readers/get-line-number reader))
+  (get-column-number [reader]
+    (readers/get-column-number reader))
+  (get-file-name [reader]
+    (readers/get-file-name reader)))
+
+(extend-protocol vendor/ReaderCoercer
+  clojure.tools.reader.reader_types.ReaderCoercer
+  (to-rdr [reader]
+    (readers/to-rdr reader)))
+
+(extend-protocol vendor/PushbackReaderCoercer
+  clojure.tools.reader.reader_types.PushbackReaderCoercer
+  (to-pbr [reader buflen]
+    (readers/to-pbr reader buflen)))