summaryrefslogtreecommitdiff
path: root/ext/json/lib/json/common.rb
blob: d58c7eae90725b330c29b6b0934520512fd77888 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
#frozen_string_literal: false
require 'json/version'
require 'json/generic_object'

module JSON
  class << self
    # :call-seq:
    #   JSON[object] -> new_array or new_string
    #
    # If +object+ is a \String,
    # calls JSON.parse with +object+ and +opts+ (see method #parse):
    #   json = '[0, 1, null]'
    #   JSON[json]# => [0, 1, nil]
    #
    # Otherwise, calls JSON.generate with +object+ and +opts+ (see method #generate):
    #   ruby = [0, 1, nil]
    #   JSON[ruby] # => '[0,1,null]'
    def [](object, opts = {})
      if object.respond_to? :to_str
        JSON.parse(object.to_str, opts)
      else
        JSON.generate(object, opts)
      end
    end

    # Returns the JSON parser class that is used by JSON. This is either
    # JSON::Ext::Parser or JSON::Pure::Parser:
    #   JSON.parser # => JSON::Ext::Parser
    attr_reader :parser

    # Set the JSON parser class _parser_ to be used by JSON.
    def parser=(parser) # :nodoc:
      @parser = parser
      remove_const :Parser if const_defined?(:Parser, false)
      const_set :Parser, parser
    end

    # Return the constant located at _path_. The format of _path_ has to be
    # either ::A::B::C or A::B::C. In any case, A has to be located at the top
    # level (absolute namespace path?). If there doesn't exist a constant at
    # the given path, an ArgumentError is raised.
    def deep_const_get(path) # :nodoc:
      path.to_s.split(/::/).inject(Object) do |p, c|
        case
        when c.empty?                  then p
        when p.const_defined?(c, true) then p.const_get(c)
        else
          begin
            p.const_missing(c)
          rescue NameError => e
            raise ArgumentError, "can't get const #{path}: #{e}"
          end
        end
      end
    end

    # Set the module _generator_ to be used by JSON.
    def generator=(generator) # :nodoc:
      old, $VERBOSE = $VERBOSE, nil
      @generator = generator
      generator_methods = generator::GeneratorMethods
      for const in generator_methods.constants
        klass = deep_const_get(const)
        modul = generator_methods.const_get(const)
        klass.class_eval do
          instance_methods(false).each do |m|
            m.to_s == 'to_json' and remove_method m
          end
          include modul
        end
      end
      self.state = generator::State
      const_set :State, self.state
    ensure
      $VERBOSE = old
    end

    def create_fast_state
      State.new(
        :indent         => '',
        :space          => '',
        :object_nl      => "",
        :array_nl       => "",
        :max_nesting    => false
      )
    end

    def create_pretty_state
      State.new(
        :indent         => '  ',
        :space          => ' ',
        :object_nl      => "\n",
        :array_nl       => "\n"
      )
    end

    # Returns the JSON generator module that is used by JSON. This is
    # either JSON::Ext::Generator or JSON::Pure::Generator:
    #   JSON.generator # => JSON::Ext::Generator
    attr_reader :generator

    # Sets or Returns the JSON generator state class that is used by JSON. This is
    # either JSON::Ext::Generator::State or JSON::Pure::Generator::State:
    #   JSON.state # => JSON::Ext::Generator::State
    attr_accessor :state
  end

  DEFAULT_CREATE_ID = 'json_class'.freeze
  private_constant :DEFAULT_CREATE_ID

  CREATE_ID_TLS_KEY = "JSON.create_id".freeze
  private_constant :CREATE_ID_TLS_KEY

  # Sets create identifier, which is used to decide if the _json_create_
  # hook of a class should be called; initial value is +json_class+:
  #   JSON.create_id # => 'json_class'
  def self.create_id=(new_value)
    Thread.current[CREATE_ID_TLS_KEY] = new_value.dup.freeze
  end

  # Returns the current create identifier.
  # See also JSON.create_id=.
  def self.create_id
    Thread.current[CREATE_ID_TLS_KEY] || DEFAULT_CREATE_ID
  end

  NaN           = 0.0/0

  Infinity      = 1.0/0

  MinusInfinity = -Infinity

  # The base exception for JSON errors.
  class JSONError < StandardError
    def self.wrap(exception)
      obj = new("Wrapped(#{exception.class}): #{exception.message.inspect}")
      obj.set_backtrace exception.backtrace
      obj
    end
  end

  # This exception is raised if a parser error occurs.
  class ParserError < JSONError; end

  # This exception is raised if the nesting of parsed data structures is too
  # deep.
  class NestingError < ParserError; end

  # :stopdoc:
  class CircularDatastructure < NestingError; end
  # :startdoc:

  # This exception is raised if a generator or unparser error occurs.
  class GeneratorError < JSONError; end
  # For backwards compatibility
  UnparserError = GeneratorError # :nodoc:

  # This exception is raised if the required unicode support is missing on the
  # system. Usually this means that the iconv library is not installed.
  class MissingUnicodeSupport < JSONError; end

  module_function

  # :call-seq:
  #   JSON.parse(source, opts) -> object
  #
  # Returns the Ruby objects created by parsing the given +source+.
  #
  # Argument +source+ contains the \String to be parsed.
  #
  # Argument +opts+, if given, contains a \Hash of options for the parsing.
  # See {Parsing Options}[#module-JSON-label-Parsing+Options].
  #
  # ---
  #
  # When +source+ is a \JSON array, returns a Ruby \Array:
  #   source = '["foo", 1.0, true, false, null]'
  #   ruby = JSON.parse(source)
  #   ruby # => ["foo", 1.0, true, false, nil]
  #   ruby.class # => Array
  #
  # When +source+ is a \JSON object, returns a Ruby \Hash:
  #   source = '{"a": "foo", "b": 1.0, "c": true, "d": false, "e": null}'
  #   ruby = JSON.parse(source)
  #   ruby # => {"a"=>"foo", "b"=>1.0, "c"=>true, "d"=>false, "e"=>nil}
  #   ruby.class # => Hash
  #
  # For examples of parsing for all \JSON data types, see
  # {Parsing \JSON}[#module-JSON-label-Parsing+JSON].
  #
  # Parses nested JSON objects:
  #   source = <<-EOT
  #   {
  #   "name": "Dave",
  #     "age" :40,
  #     "hats": [
  #       "Cattleman's",
  #       "Panama",
  #       "Tophat"
  #     ]
  #   }
  #   EOT
  #   ruby = JSON.parse(source)
  #   ruby # => {"name"=>"Dave", "age"=>40, "hats"=>["Cattleman's", "Panama", "Tophat"]}
  #
  # ---
  #
  # Raises an exception if +source+ is not valid JSON:
  #   # Raises JSON::ParserError (783: unexpected token at ''):
  #   JSON.parse('')
  #
  def parse(source, opts = {})
    Parser.new(source, **(opts||{})).parse
  end

  # :call-seq:
  #   JSON.parse!(source, opts) -> object
  #
  # Calls
  #   parse(source, opts)
  # with +source+ and possibly modified +opts+.
  #
  # Differences from JSON.parse:
  # - Option +max_nesting+, if not provided, defaults to +false+,
  #   which disables checking for nesting depth.
  # - Option +allow_nan+, if not provided, defaults to +true+.
  def parse!(source, opts = {})
    opts = {
      :max_nesting  => false,
      :allow_nan    => true
    }.merge(opts)
    Parser.new(source, **(opts||{})).parse
  end

  # :call-seq:
  #   JSON.load_file(path, opts={}) -> object
  #
  # Calls:
  #   parse(File.read(path), opts)
  #
  # See method #parse.
  def load_file(filespec, opts = {})
    parse(File.read(filespec), opts)
  end

  # :call-seq:
  #   JSON.load_file!(path, opts = {})
  #
  # Calls:
  #   JSON.parse!(File.read(path, opts))
  #
  # See method #parse!
  def load_file!(filespec, opts = {})
    parse!(File.read(filespec), opts)
  end

  # :call-seq:
  #   JSON.generate(obj, opts = nil) -> new_string
  #
  # Returns a \String containing the generated \JSON data.
  #
  # See also JSON.fast_generate, JSON.pretty_generate.
  #
  # Argument +obj+ is the Ruby object to be converted to \JSON.
  #
  # Argument +opts+, if given, contains a \Hash of options for the generation.
  # See {Generating Options}[#module-JSON-label-Generating+Options].
  #
  # ---
  #
  # When +obj+ is an \Array, returns a \String containing a \JSON array:
  #   obj = ["foo", 1.0, true, false, nil]
  #   json = JSON.generate(obj)
  #   json # => '["foo",1.0,true,false,null]'
  #
  # When +obj+ is a \Hash, returns a \String containing a \JSON object:
  #   obj = {foo: 0, bar: 's', baz: :bat}
  #   json = JSON.generate(obj)
  #   json # => '{"foo":0,"bar":"s","baz":"bat"}'
  #
  # For examples of generating from other Ruby objects, see
  # {Generating \JSON from Other Objects}[#module-JSON-label-Generating+JSON+from+Other+Objects].
  #
  # ---
  #
  # Raises an exception if any formatting option is not a \String.
  #
  # Raises an exception if +obj+ contains circular references:
  #   a = []; b = []; a.push(b); b.push(a)
  #   # Raises JSON::NestingError (nesting of 100 is too deep):
  #   JSON.generate(a)
  #
  def generate(obj, opts = nil)
    if State === opts
      state, opts = opts, nil
    else
      state = State.new
    end
    if opts
      if opts.respond_to? :to_hash
        opts = opts.to_hash
      elsif opts.respond_to? :to_h
        opts = opts.to_h
      else
        raise TypeError, "can't convert #{opts.class} into Hash"
      end
      state = state.configure(opts)
    end
    state.generate(obj)
  end

  # :stopdoc:
  # I want to deprecate these later, so I'll first be silent about them, and
  # later delete them.
  alias unparse generate
  module_function :unparse
  # :startdoc:

  # :call-seq:
  #   JSON.fast_generate(obj, opts) -> new_string
  #
  # Arguments +obj+ and +opts+ here are the same as
  # arguments +obj+ and +opts+ in JSON.generate.
  #
  # By default, generates \JSON data without checking
  # for circular references in +obj+ (option +max_nesting+ set to +false+, disabled).
  #
  # Raises an exception if +obj+ contains circular references:
  #   a = []; b = []; a.push(b); b.push(a)
  #   # Raises SystemStackError (stack level too deep):
  #   JSON.fast_generate(a)
  def fast_generate(obj, opts = nil)
    if State === opts
      state, opts = opts, nil
    else
      state = JSON.create_fast_state
    end
    if opts
      if opts.respond_to? :to_hash
        opts = opts.to_hash
      elsif opts.respond_to? :to_h
        opts = opts.to_h
      else
        raise TypeError, "can't convert #{opts.class} into Hash"
      end
      state.configure(opts)
    end
    state.generate(obj)
  end

  # :stopdoc:
  # I want to deprecate these later, so I'll first be silent about them, and later delete them.
  alias fast_unparse fast_generate
  module_function :fast_unparse
  # :startdoc:

  # :call-seq:
  #   JSON.pretty_generate(obj, opts = nil) -> new_string
  #
  # Arguments +obj+ and +opts+ here are the same as
  # arguments +obj+ and +opts+ in JSON.generate.
  #
  # Default options are:
  #   {
  #     indent: '  ',   # Two spaces
  #     space: ' ',     # One space
  #     array_nl: "\n", # Newline
  #     object_nl: "\n" # Newline
  #   }
  #
  # Example:
  #   obj = {foo: [:bar, :baz], bat: {bam: 0, bad: 1}}
  #   json = JSON.pretty_generate(obj)
  #   puts json
  # Output:
  #   {
  #     "foo": [
  #       "bar",
  #       "baz"
  #     ],
  #     "bat": {
  #       "bam": 0,
  #       "bad": 1
  #     }
  #   }
  #
  def pretty_generate(obj, opts = nil)
    if State === opts
      state, opts = opts, nil
    else
      state = JSON.create_pretty_state
    end
    if opts
      if opts.respond_to? :to_hash
        opts = opts.to_hash
      elsif opts.respond_to? :to_h
        opts = opts.to_h
      else
        raise TypeError, "can't convert #{opts.class} into Hash"
      end
      state.configure(opts)
    end
    state.generate(obj)
  end

  # :stopdoc:
  # I want to deprecate these later, so I'll first be silent about them, and later delete them.
  alias pretty_unparse pretty_generate
  module_function :pretty_unparse
  # :startdoc:

  class << self
    # Sets or returns default options for the JSON.load method.
    # Initially:
    #   opts = JSON.load_default_options
    #   opts # => {:max_nesting=>false, :allow_nan=>true, :allow_blank=>true, :create_additions=>true}
    attr_accessor :load_default_options
  end
  self.load_default_options = {
    :max_nesting      => false,
    :allow_nan        => true,
    :allow_blank       => true,
    :create_additions => true,
  }

  # :call-seq:
  #   JSON.load(source, proc = nil, options = {}) -> object
  #
  # Returns the Ruby objects created by parsing the given +source+.
  #
  # - Argument +source+ must be, or be convertible to, a \String:
  #   - If +source+ responds to instance method +to_str+,
  #     <tt>source.to_str</tt> becomes the source.
  #   - If +source+ responds to instance method +to_io+,
  #     <tt>source.to_io.read</tt> becomes the source.
  #   - If +source+ responds to instance method +read+,
  #     <tt>source.read</tt> becomes the source.
  #   - If both of the following are true, source becomes the \String <tt>'null'</tt>:
  #     - Option +allow_blank+ specifies a truthy value.
  #     - The source, as defined above, is +nil+ or the empty \String <tt>''</tt>.
  #   - Otherwise, +source+ remains the source.
  # - Argument +proc+, if given, must be a \Proc that accepts one argument.
  #   It will be called recursively with each result (depth-first order).
  #   See details below.
  #   BEWARE: This method is meant to serialise data from trusted user input,
  #   like from your own database server or clients under your control, it could
  #   be dangerous to allow untrusted users to pass JSON sources into it.
  # - Argument +opts+, if given, contains a \Hash of options for the parsing.
  #   See {Parsing Options}[#module-JSON-label-Parsing+Options].
  #   The default options can be changed via method JSON.load_default_options=.
  #
  # ---
  #
  # When no +proc+ is given, modifies +source+ as above and returns the result of
  # <tt>parse(source, opts)</tt>;  see #parse.
  #
  # Source for following examples:
  #   source = <<-EOT
  #   {
  #   "name": "Dave",
  #     "age" :40,
  #     "hats": [
  #       "Cattleman's",
  #       "Panama",
  #       "Tophat"
  #     ]
  #   }
  #   EOT
  #
  # Load a \String:
  #   ruby = JSON.load(source)
  #   ruby # => {"name"=>"Dave", "age"=>40, "hats"=>["Cattleman's", "Panama", "Tophat"]}
  #
  # Load an \IO object:
  #   require 'stringio'
  #   object = JSON.load(StringIO.new(source))
  #   object # => {"name"=>"Dave", "age"=>40, "hats"=>["Cattleman's", "Panama", "Tophat"]}
  #
  # Load a \File object:
  #   path = 't.json'
  #   File.write(path, source)
  #   File.open(path) do |file|
  #     JSON.load(file)
  #   end # => {"name"=>"Dave", "age"=>40, "hats"=>["Cattleman's", "Panama", "Tophat"]}
  #
  # ---
  #
  # When +proc+ is given:
  # - Modifies +source+ as above.
  # - Gets the +result+ from calling <tt>parse(source, opts)</tt>.
  # - Recursively calls <tt>proc(result)</tt>.
  # - Returns the final result.
  #
  # Example:
  #   require 'json'
  #
  #   # Some classes for the example.
  #   class Base
  #     def initialize(attributes)
  #       @attributes = attributes
  #     end
  #   end
  #   class User    < Base; end
  #   class Account < Base; end
  #   class Admin   < Base; end
  #   # The JSON source.
  #   json = <<-EOF
  #   {
  #     "users": [
  #         {"type": "User", "username": "jane", "email": "jane@example.com"},
  #         {"type": "User", "username": "john", "email": "john@example.com"}
  #     ],
  #     "accounts": [
  #         {"account": {"type": "Account", "paid": true, "account_id": "1234"}},
  #         {"account": {"type": "Account", "paid": false, "account_id": "1235"}}
  #     ],
  #     "admins": {"type": "Admin", "password": "0wn3d"}
  #   }
  #   EOF
  #   # Deserializer method.
  #   def deserialize_obj(obj, safe_types = %w(User Account Admin))
  #     type = obj.is_a?(Hash) && obj["type"]
  #     safe_types.include?(type) ? Object.const_get(type).new(obj) : obj
  #   end
  #   # Call to JSON.load
  #   ruby = JSON.load(json, proc {|obj|
  #     case obj
  #     when Hash
  #       obj.each {|k, v| obj[k] = deserialize_obj v }
  #     when Array
  #       obj.map! {|v| deserialize_obj v }
  #     end
  #   })
  #   pp ruby
  # Output:
  #   {"users"=>
  #      [#<User:0x00000000064c4c98
  #        @attributes=
  #          {"type"=>"User", "username"=>"jane", "email"=>"jane@example.com"}>,
  #        #<User:0x00000000064c4bd0
  #        @attributes=
  #          {"type"=>"User", "username"=>"john", "email"=>"john@example.com"}>],
  #    "accounts"=>
  #      [{"account"=>
  #          #<Account:0x00000000064c4928
  #          @attributes={"type"=>"Account", "paid"=>true, "account_id"=>"1234"}>},
  #       {"account"=>
  #          #<Account:0x00000000064c4680
  #          @attributes={"type"=>"Account", "paid"=>false, "account_id"=>"1235"}>}],
  #    "admins"=>
  #      #<Admin:0x00000000064c41f8
  #      @attributes={"type"=>"Admin", "password"=>"0wn3d"}>}
  #
  def load(source, proc = nil, options = {})
    opts = load_default_options.merge options
    if source.respond_to? :to_str
      source = source.to_str
    elsif source.respond_to? :to_io
      source = source.to_io.read
    elsif source.respond_to?(:read)
      source = source.read
    end
    if opts[:allow_blank] && (source.nil? || source.empty?)
      source = 'null'
    end
    result = parse(source, opts)
    recurse_proc(result, &proc) if proc
    result
  end

  # Recursively calls passed _Proc_ if the parsed data structure is an _Array_ or _Hash_
  def recurse_proc(result, &proc) # :nodoc:
    case result
    when Array
      result.each { |x| recurse_proc x, &proc }
      proc.call result
    when Hash
      result.each { |x, y| recurse_proc x, &proc; recurse_proc y, &proc }
      proc.call result
    else
      proc.call result
    end
  end

  alias restore load
  module_function :restore

  class << self
    # Sets or returns the default options for the JSON.dump method.
    # Initially:
    #   opts = JSON.dump_default_options
    #   opts # => {:max_nesting=>false, :allow_nan=>true, :escape_slash=>false}
    attr_accessor :dump_default_options
  end
  self.dump_default_options = {
    :max_nesting => false,
    :allow_nan   => true,
    :escape_slash => false,
  }

  # :call-seq:
  #   JSON.dump(obj, io = nil, limit = nil)
  #
  # Dumps +obj+ as a \JSON string, i.e. calls generate on the object and returns the result.
  #
  # The default options can be changed via method JSON.dump_default_options.
  #
  # - Argument +io+, if given, should respond to method +write+;
  #   the \JSON \String is written to +io+, and +io+ is returned.
  #   If +io+ is not given, the \JSON \String is returned.
  # - Argument +limit+, if given, is passed to JSON.generate as option +max_nesting+.
  #
  # ---
  #
  # When argument +io+ is not given, returns the \JSON \String generated from +obj+:
  #   obj = {foo: [0, 1], bar: {baz: 2, bat: 3}, bam: :bad}
  #   json = JSON.dump(obj)
  #   json # => "{\"foo\":[0,1],\"bar\":{\"baz\":2,\"bat\":3},\"bam\":\"bad\"}"
  #
  # When argument +io+ is given, writes the \JSON \String to +io+ and returns +io+:
  #   path = 't.json'
  #   File.open(path, 'w') do |file|
  #     JSON.dump(obj, file)
  #   end # => #<File:t.json (closed)>
  #   puts File.read(path)
  # Output:
  #   {"foo":[0,1],"bar":{"baz":2,"bat":3},"bam":"bad"}
  def dump(obj, anIO = nil, limit = nil)
    if anIO and limit.nil?
      anIO = anIO.to_io if anIO.respond_to?(:to_io)
      unless anIO.respond_to?(:write)
        limit = anIO
        anIO = nil
      end
    end
    opts = JSON.dump_default_options
    opts = opts.merge(:max_nesting => limit) if limit
    result = generate(obj, opts)
    if anIO
      anIO.write result
      anIO
    else
      result
    end
  rescue JSON::NestingError
    raise ArgumentError, "exceed depth limit"
  end

  # Encodes string using String.encode.
  def self.iconv(to, from, string)
    string.encode(to, from)
  end
end

module ::Kernel
  private

  # Outputs _objs_ to STDOUT as JSON strings in the shortest form, that is in
  # one line.
  def j(*objs)
    objs.each do |obj|
      puts JSON::generate(obj, :allow_nan => true, :max_nesting => false)
    end
    nil
  end

  # Outputs _objs_ to STDOUT as JSON strings in a pretty format, with
  # indentation and over many lines.
  def jj(*objs)
    objs.each do |obj|
      puts JSON::pretty_generate(obj, :allow_nan => true, :max_nesting => false)
    end
    nil
  end

  # If _object_ is string-like, parse the string and return the parsed result as
  # a Ruby data structure. Otherwise, generate a JSON text from the Ruby data
  # structure object and return it.
  #
  # The _opts_ argument is passed through to generate/parse respectively. See
  # generate and parse for their documentation.
  def JSON(object, *args)
    if object.respond_to? :to_str
      JSON.parse(object.to_str, args.first)
    else
      JSON.generate(object, args.first)
    end
  end
end

# Extends any Class to include _json_creatable?_ method.
class ::Class
  # Returns true if this class can be used to create an instance
  # from a serialised JSON string. The class has to implement a class
  # method _json_create_ that expects a hash as first parameter. The hash
  # should include the required data.
  def json_creatable?
    respond_to?(:json_create)
  end
end