From d18cc7e763192adbb9ca52eede99c4f1365a6b6a Mon Sep 17 00:00:00 2001
From: Brandon Bloom <brandon@brandonbloom.name>
Date: Mon, 18 Jun 2012 01:14:46 -0700
Subject: [PATCH] Implement with-out-str; also fixes CLJS-319

---
 src/clj/cljs/core.clj         |   12 +++++++-
 src/cljs/cljs/core.cljs       |   61 +++++++++++++----------------------------
 test/cljs/cljs/core_test.cljs |    2 +
 3 files changed, 32 insertions(+), 43 deletions(-)

diff --git a/src/clj/cljs/core.clj b/src/clj/cljs/core.clj
index 70c1509..4f41636 100644
--- a/src/clj/cljs/core.clj
+++ b/src/clj/cljs/core.clj
@@ -1041,4 +1041,14 @@
          (if (zero? ~'argc)
            (~'f)
            ~(gen-apply-to-helper))))
-     (set! ~'*unchecked-if* false)))
\ No newline at end of file
+     (set! ~'*unchecked-if* false)))
+
+(defmacro with-out-str
+  "Evaluates exprs in a context in which *print-fn* is bound to .append
+  on a fresh StringBuffer.  Returns the string created by any nested
+  printing calls."
+  [& body]
+  `(let [sb# (goog.string/StringBuffer.)]
+     (binding [cljs.core/*print-fn* (fn [x#] (.append sb# x#))]
+       ~@body)
+     (cljs.core/str sb#)))
diff --git a/src/cljs/cljs/core.cljs b/src/cljs/cljs/core.cljs
index cbea7d9..a575db4 100644
--- a/src/cljs/cljs/core.cljs
+++ b/src/cljs/cljs/core.cljs
@@ -17,7 +17,7 @@
 (def
   ^{:doc "Each runtime environment provides a diffenent way to print output.
   Whatever function *print-fn* is bound to will be passed any
-  Strings which should be printed."}
+  Strings which should be printed." :dynamic true}
   *print-fn*
   (fn [_]
     (throw (js/Error. "No *print-fn* fn set for evaluation environment"))))
@@ -6104,39 +6104,16 @@ reduces them without incurring seq initialization"
 
              :else (list "#<" (str obj) ">")))))
 
-(defn- pr-sb [objs opts]
-  (let [first-obj (first objs)
-        sb (gstring/StringBuffer.)]
-    (doseq [obj objs]
-      (when-not (identical? obj first-obj)
-        (.append sb " "))
-      (doseq [string (pr-seq obj opts)]
-        (.append sb string)))
-    sb))
-
-(defn pr-str-with-opts
-  "Prints a sequence of objects to a string, observing all the
-  options given in opts"
-  [objs opts]
-  (str (pr-sb objs opts)))
-
-(defn prn-str-with-opts
-  "Same as pr-str-with-opts followed by (newline)"
-  [objs opts]
-  (let [sb (pr-sb objs opts)]
-    (.append sb \newline)
-    (str sb)))
-
 (defn pr-with-opts
   "Prints a sequence of objects using string-print, observing all
   the options given in opts"
   [objs opts]
-  (let [first-obj (first objs)]
-    (doseq [obj objs]
-      (when-not (identical? obj first-obj)
-        (string-print " "))
-      (doseq [string (pr-seq obj opts)]
-        (string-print string)))))
+  (doseq [string (pr-seq (first objs) opts)]
+    (string-print string))
+  (doseq [obj (next objs)]
+    (string-print " ")
+    (doseq [string (pr-seq obj opts)]
+      (string-print string))))
 
 (defn newline [opts]
   (string-print "\n")
@@ -6154,16 +6131,6 @@ reduces them without incurring seq initialization"
    :meta *print-meta*
    :dup *print-dup*})
 
-(defn pr-str
-  "pr to a string, returning it. Fundamental entrypoint to IPrintable."
-  [& objs]
-  (pr-str-with-opts objs (pr-opts)))
-
-(defn prn-str
-  "Same as pr-str followed by (newline)"
-  [& objs]
-  (prn-str-with-opts objs (pr-opts)))
-
 (defn pr
   "Prints the object(s) using string-print.  Prints the
   object(s), separated by spaces if there is more than one.
@@ -6172,6 +6139,11 @@ reduces them without incurring seq initialization"
   [& objs]
   (pr-with-opts objs (pr-opts)))
 
+(defn pr-str
+  "pr to a string, returning it. Fundamental entrypoint to IPrintable."
+  [& objs]
+  (with-out-str (apply pr objs)))
+
 (def ^{:doc
   "Prints the object(s) using string-print.
   print and println produce output for human consumption."}
@@ -6182,7 +6154,7 @@ reduces them without incurring seq initialization"
 (defn print-str
   "print to a string, returning it"
   [& objs]
-  (pr-str-with-opts objs (assoc (pr-opts) :readably false)))
+  (with-out-str (apply print objs)))
 
 (defn println
   "Same as print followed by (newline)"
@@ -6193,7 +6165,7 @@ reduces them without incurring seq initialization"
 (defn println-str
   "println to a string, returning it"
   [& objs]
-  (prn-str-with-opts objs (assoc (pr-opts) :readably false)))
+  (with-out-str (apply println objs)))
 
 (defn prn
   "Same as pr followed by (newline)."
@@ -6201,6 +6173,11 @@ reduces them without incurring seq initialization"
   (pr-with-opts objs (pr-opts))
   (newline (pr-opts)))
 
+(defn prn-str
+  "Same as pr-str followed by (newline)"
+  [& objs]
+  (with-out-str (apply prn objs)))
+
 (extend-protocol IPrintable
   boolean
   (-pr-seq [bool opts] (list (str bool)))
diff --git a/test/cljs/cljs/core_test.cljs b/test/cljs/cljs/core_test.cljs
index eae66ac..a7825ee 100644
--- a/test/cljs/cljs/core_test.cljs
+++ b/test/cljs/cljs/core_test.cljs
@@ -213,6 +213,7 @@
              (assoc (cljs.core.ObjMap. nil (array) (js-obj)) :foo 5)))
 
   (assert (= "\"asdf\"" (pr-str "asdf")))
+  (assert (= "1 1 2 2" (pr-str 1 1 2 2)))
   (assert (= "[1 true {:a 2, :b #\"x\\\"y\"} #<Array [3, 4]>]"
              (pr-str [1 true {:a 2 :b #"x\"y"} (array 3 4)])))
 
@@ -220,6 +221,7 @@
   (assert (= "[1 true {:a 2, :b 42} #<Array [3, 4]>]\n"
              (prn-str [1 true {:a 2 :b 42} (array 3 4)])))
 
+  (assert (= "12" (with-out-str (print 1) (print 2))))
   (assert (= "asdf" (print-str "asdf")))
   (assert (= "asdf\n" (println-str "asdf")))
 
-- 
1.7.9.1