Moved print_json.clj to json/write.clj; added json/read.clj.

2 files changed, 172 insertions, 2 deletions

diff --git a/src/clojure/contrib/json/read.clj b/src/clojure/contrib/json/read.clj
new file mode 100644
index 00000000..897351be
--- /dev/null
+++ b/src/clojure/contrib/json/read.clj
@@ -0,0 +1,170 @@
+;;; json/read.clj: JavaScript Object Notation (JSON) parser
+
+;; by Stuart Sierra, http://stuartsierra.com/
+;; January 26, 2009
+
+;; Copyright (c) Stuart Sierra, 2009. 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.
+
+
+
+;; For more information on JSON, see http://www.json.org/
+
+
+
+(ns clojure.contrib.json.read
+  (:import (java.io PushbackReader StringReader EOFException))
+  (:use [clojure.contrib.test-is :only (deftest is)]))
+
+(declare read-json)
+
+(defn- read-json-array [stream]
+  ;; Expects to be called with the head of the stream AFTER the
+  ;; opening bracket.
+  (loop [i (.read stream), result []]
+    (let [c (char i)]
+      (cond
+       (= i -1) (throw (EOFException. "JSON error (end-of-file inside array)"))
+       (Character/isWhitespace c) (recur (.read stream) result)
+       (= c \,) (recur (char (.read stream)) result)
+       (= c \]) result
+       :else (do (.unread stream (int c))
+                 (let [element (read-json stream)]
+                   (recur (.read stream) (conj result element))))))))
+
+(defn- read-json-object [stream]
+  ;; Expects to be called with the head of the stream AFTER the
+  ;; opening bracket.
+  (loop [i (.read stream), key nil, result {}]
+    (let [c (char i)]
+      (cond
+       (= i -1) (throw (EOFException. "JSON error (end-of-file inside object)"))
+
+       (Character/isWhitespace c) (recur (.read stream) key result)
+
+       (= c \,) (recur (.read stream) nil result)
+
+       (= c \:) (recur (.read stream) key result)
+
+       (= c \}) (if (nil? key)
+                  result
+                  (throw (Exception. "JSON error (key missing value in object)")))
+
+       :else (do (.unread stream i)
+                 (let [element (read-json stream)]
+                   (if (nil? key)
+                     (if (string? element)
+                       (recur (.read stream) element result)
+                       (throw (Exception. "JSON error (non-string key in object)")))
+                     (recur (.read stream) nil (assoc result key element)))))))))
+
+(defn read-json
+  "Read the next JSON record from stream, which must be an instance of
+  java.io.PushbackReader."
+  ([] (read-json *in* true nil))
+  ([stream] (read-json stream true nil))
+  ([stream eof-error? eof-value]
+     (loop [i (.read stream)]
+       (let [c (char i)]
+         (cond
+          ;; Handle end-of-stream
+          (= i -1) (if eof-error?
+                     (throw (EOFException. "JSON error (end-of-file)"))
+                     eof-value)
+
+          ;; Ignore whitespace
+          (Character/isWhitespace c) (recur (.read stream))
+
+          ;; Read strings, numbers, true, and false with Clojure reader
+          (#{\" \- \0 \1 \2 \3 \4 \5 \6 \7 \8 \9} c)
+          (do (.unread stream i)
+              (read stream true nil))
+
+          ;; Read null as nil
+          (= c \n) (let [ull [(char (.read stream))
+                              (char (.read stream))
+                              (char (.read stream))]]
+                     (if (= ull [\u \l \l])
+                       nil
+                       (throw (Exception. (str "JSON error (expected null): " c ull)))))
+
+          ;; Read true
+          (= c \t) (let [rue [(char (.read stream))
+                              (char (.read stream))
+                              (char (.read stream))]]
+                     (if (= rue [\r \u \e])
+                       true
+                       (throw (Exception. (str "JSON error (expected true): " c rue)))))
+
+          ;; Read false
+          (= c \f) (let [alse [(char (.read stream))
+                               (char (.read stream))
+                               (char (.read stream))
+                               (char (.read stream))]]
+                     (if (= alse [\a \l \s \e])
+                       false
+                       (throw (Exception. (str "JSON error (expected false): " c alse)))))
+
+          
+
+          ;; Read JSON objects
+          (= c \{) (read-json-object stream)
+
+          ;; Read JSON arrays
+          (= c \[) (read-json-array stream)
+
+          :else (throw (Exception. (str "JSON error (unexpected character): " c))))))))
+
+
+(defn read-json-string [string]
+  (read-json (PushbackReader. (StringReader. string))))
+
+
+;;; TESTS
+
+(deftest can-read-numbers
+  (is (= 42 (read-json-string "42")))
+  (is (= -3 (read-json-string "-3")))
+  (is (= 3.14159 (read-json-string "3.14159")))
+  (is (= 6.022e23 (read-json-string "6.022e23"))))
+
+(deftest can-read-null
+  (is (= nil (read-json-string "null"))))
+
+(deftest can-read-strings
+  (is (= "Hello, World!" (read-json-string "\"Hello, World!\""))))
+
+(deftest can-read-booleans
+  (is (= true (read-json-string "true")))
+  (is (= false (read-json-string "false"))))
+
+(deftest can-ignore-whitespace
+  (is (= nil (read-json-string "\r\n   null"))))
+
+(deftest can-read-arrays
+  (is (= [1 2 3] (read-json-string "[1,2,3]")))
+  (is (= ["Ole" "Lena"] (read-json-string "[\"Ole\", \r\n \"Lena\"]"))))
+
+(deftest can-read-objects
+  (is (= {"a" 1, "b" 2} (read-json-string "{\"a\": 1, \"b\": 2}"))))
+
+(deftest can-read-nested-structures
+  (is (= {"a" [1 2 {"b" [3 "four"]} 5.5]}
+         (read-json-string "{\"a\":[1,2,{\"b\":[3,\"four\"]},5.5]}"))))
+
+(deftest disallows-non-string-keys
+  (is (thrown? Exception (read-json-string "{26:\"z\""))))
+
+(deftest disallows-barewords
+  (is (thrown? Exception (read-json-string "  foo  "))))
+
+(deftest disallows-unclosed-arrays
+  (is (thrown? Exception (read-json-string "[1, 2,  "))))
+
+(deftest disallows-unclosed-objects
+  (is (thrown? Exception (read-json-string "{\"a\":1,  "))))
diff --git a/src/clojure/contrib/print_json.clj b/src/clojure/contrib/json/write.clj
index 1368e741..4b6a1f9a 100644
--- a/src/clojure/contrib/print_json.clj
+++ b/src/clojure/contrib/json/write.clj
@@ -1,4 +1,4 @@
-;;; print_json.clj: JavaScript Object Notation (JSON) generator
+;;; json/write.clj: JavaScript Object Notation (JSON) generator
 
 ;; by Stuart Sierra, http://stuartsierra.com/
 ;; January 26, 2009
@@ -17,7 +17,7 @@
 
 
 
-(ns clojure.contrib.print-json
+(ns clojure.contrib.json.write
   (:use [clojure.contrib.test-is :only (deftest is)]))
 
 (defmulti