1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/clojure/contrib/test_contrib/pprint/examples/json.clj	Sat Aug 21 06:25:44 2010 -0400
     1.3 @@ -0,0 +1,142 @@
     1.4 +;;; json.clj: A pretty printing version of the JavaScript Object Notation (JSON) generator
     1.5 +
     1.6 +;; by Tom Faulhaber, based on the version by Stuart Sierra (clojure.contrib.json.write)
     1.7 +;; May 9, 2009
     1.8 +
     1.9 +;; Copyright (c) Tom Faulhaber/Stuart Sierra, 2009. All rights reserved.  The use
    1.10 +;; and distribution terms for this software are covered by the Eclipse
    1.11 +;; Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
    1.12 +;; which can be found in the file epl-v10.html at the root of this
    1.13 +;; distribution.  By using this software in any fashion, you are
    1.14 +;; agreeing to be bound by the terms of this license.  You must not
    1.15 +;; remove this notice, or any other, from this software.
    1.16 +
    1.17 +
    1.18 +(ns 
    1.19 +  #^{:author "Tom Faulhaber (based on the version by Stuart Sierra)",
    1.20 +     :doc "Pretty printing JavaScript Object Notation (JSON) generator.
    1.21 +
    1.22 +This is an example of using a pretty printer dispatch function to generate JSON output",
    1.23 +     :see-also [["http://json.org/", "JSON Home Page"]]}
    1.24 +  clojure.contrib.pprint.examples.json
    1.25 +  (:use [clojure.test :only (deftest- is)]
    1.26 +        [clojure.contrib.string :only (as-str)]
    1.27 +        [clojure.contrib.pprint :only (write formatter-out)]))
    1.28 +
    1.29 +
    1.30 +
    1.31 +(defmulti dispatch-json
    1.32 +  "The dispatch function for printing objects as JSON"
    1.33 +  {:arglists '[[x]]} 
    1.34 +  (fn [x] (cond
    1.35 +            (nil? x) nil ;; prevent NullPointerException on next line
    1.36 +            (.isArray (class x)) ::array
    1.37 +            :else (type x))))
    1.38 +
    1.39 +;; Primitive types can be printed with Clojure's pr function.
    1.40 +(derive java.lang.Boolean ::pr)
    1.41 +(derive java.lang.Byte ::pr)
    1.42 +(derive java.lang.Short ::pr)
    1.43 +(derive java.lang.Integer ::pr)
    1.44 +(derive java.lang.Long ::pr)
    1.45 +(derive java.lang.Float ::pr)
    1.46 +(derive java.lang.Double ::pr)
    1.47 +
    1.48 +;; Collection types can be printed as JSON objects or arrays.
    1.49 +(derive java.util.Map ::object)
    1.50 +(derive java.util.Collection ::array)
    1.51 +
    1.52 +;; Symbols and keywords are converted to strings.
    1.53 +(derive clojure.lang.Symbol ::symbol)
    1.54 +(derive clojure.lang.Keyword ::symbol)
    1.55 +
    1.56 +
    1.57 +(defmethod dispatch-json ::pr [x] (pr x))
    1.58 +
    1.59 +(defmethod dispatch-json nil [x] (print "null"))
    1.60 +
    1.61 +(defmethod dispatch-json ::symbol [x] (pr (name x)))
    1.62 +
    1.63 +(defmethod dispatch-json ::array [s] 
    1.64 +  ((formatter-out "~<[~;~@{~w~^, ~:_~}~;]~:>") s))
    1.65 +
    1.66 +(defmethod dispatch-json ::object [m]
    1.67 +  ((formatter-out "~<{~;~@{~<~w:~_~w~:>~^, ~_~}~;}~:>") 
    1.68 +   (for [[k v] m] [(as-str k) v])))
    1.69 +
    1.70 +(defmethod dispatch-json java.lang.CharSequence [s]
    1.71 +  (print \")
    1.72 +  (dotimes [i (count s)]
    1.73 +    (let [cp (Character/codePointAt s i)]
    1.74 +      (cond
    1.75 +        ;; Handle printable JSON escapes before ASCII
    1.76 +        (= cp 34) (print "\\\"")
    1.77 +        (= cp 92) (print "\\\\")
    1.78 +        ;; Print simple ASCII characters
    1.79 +        (< 31 cp 127) (print (.charAt s i))
    1.80 +        ;; Handle non-printable JSON escapes
    1.81 +        (= cp 8) (print "\\b")
    1.82 +        (= cp 12) (print "\\f")
    1.83 +        (= cp 10) (print "\\n")
    1.84 +        (= cp 13) (print "\\r")
    1.85 +        (= cp 9) (print "\\t")
    1.86 +        ;; Any other character is printed as Hexadecimal escape
    1.87 +        :else (printf "\\u%04x" cp))))
    1.88 +  (print \"))
    1.89 +
    1.90 +(defn print-json 
    1.91 +  "Prints x as JSON.  Nil becomes JSON null.  Keywords become
    1.92 +  strings, without the leading colon.  Maps become JSON objects, all
    1.93 +  other collection types become JSON arrays.  Java arrays become JSON
    1.94 +  arrays.  Unicode characters in strings are escaped as \\uXXXX.
    1.95 +  Numbers print as with pr."
    1.96 +  [x] 
    1.97 +  (write x :dispatch dispatch-json))
    1.98 +
    1.99 +(defn json-str
   1.100 +  "Converts x to a JSON-formatted string."
   1.101 +  [x]
   1.102 +  (with-out-str (print-json x)))
   1.103 +
   1.104 +
   1.105 +
   1.106 +;;; TESTS
   1.107 +
   1.108 +;; Run these tests with
   1.109 +;; (clojure.test/run-tests 'clojure.contrib.print-json)
   1.110 +
   1.111 +;; Bind clojure.test/*load-tests* to false to omit these
   1.112 +;; tests from production code.
   1.113 +
   1.114 +(deftest- can-print-json-strings
   1.115 +  (is (= "\"Hello, World!\"" (json-str "Hello, World!")))
   1.116 +  (is (= "\"\\\"Embedded\\\" Quotes\"" (json-str "\"Embedded\" Quotes"))))
   1.117 +
   1.118 +(deftest- can-print-unicode
   1.119 +  (is (= "\"\\u1234\\u4567\"" (json-str "\u1234\u4567"))))
   1.120 +
   1.121 +(deftest- can-print-json-null
   1.122 +  (is (= "null" (json-str nil))))
   1.123 +
   1.124 +(deftest- can-print-json-arrays
   1.125 +  (is (= "[1, 2, 3]" (json-str [1 2 3])))
   1.126 +  (is (= "[1, 2, 3]" (json-str (list 1 2 3))))
   1.127 +  (is (= "[1, 2, 3]" (json-str (sorted-set 1 2 3))))
   1.128 +  (is (= "[1, 2, 3]" (json-str (seq [1 2 3])))))
   1.129 +
   1.130 +(deftest- can-print-java-arrays
   1.131 +  (is (= "[1, 2, 3]" (json-str (into-array [1 2 3])))))
   1.132 +
   1.133 +(deftest- can-print-empty-arrays
   1.134 +  (is (= "[]" (json-str [])))
   1.135 +  (is (= "[]" (json-str (list))))
   1.136 +  (is (= "[]" (json-str #{}))))
   1.137 +
   1.138 +(deftest- can-print-json-objects
   1.139 +  (is (= "{\"a\":1, \"b\":2}" (json-str (sorted-map :a 1 :b 2)))))
   1.140 +
   1.141 +(deftest- object-keys-must-be-strings
   1.142 +  (is (= "{\"1\":1, \"2\":2}" (json-str (sorted-map 1 1 2 2)))))
   1.143 +
   1.144 +(deftest- can-print-empty-objects
   1.145 +  (is (= "{}" (json-str {}))))