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Revision 1.143 by root, Fri Oct 25 20:02:54 2013 UTC vs.
Revision 1.159 by root, Wed Sep 7 17:14:56 2016 UTC

101 101
102package JSON::XS; 102package JSON::XS;
103 103
104use common::sense; 104use common::sense;
105 105
106our $VERSION = 2.34; 106our $VERSION = 3.02;
107our @ISA = qw(Exporter); 107our @ISA = qw(Exporter);
108 108
109our @EXPORT = qw(encode_json decode_json); 109our @EXPORT = qw(encode_json decode_json);
110 110
111use Exporter; 111use Exporter;
112use XSLoader; 112use XSLoader;
113
114use Types::Serialiser ();
113 115
114=head1 FUNCTIONAL INTERFACE 116=head1 FUNCTIONAL INTERFACE
115 117
116The following convenience methods are provided by this module. They are 118The following convenience methods are provided by this module. They are
117exported by default: 119exported by default:
138This function call is functionally identical to: 140This function call is functionally identical to:
139 141
140 $perl_scalar = JSON::XS->new->utf8->decode ($json_text) 142 $perl_scalar = JSON::XS->new->utf8->decode ($json_text)
141 143
142Except being faster. 144Except being faster.
143
144=item $is_boolean = JSON::XS::is_bool $scalar
145
146Returns true if the passed scalar represents either JSON::XS::true or
147JSON::XS::false, two constants that act like C<1> and C<0>, respectively
148and are used to represent JSON C<true> and C<false> values in Perl.
149
150See MAPPING, below, for more information on how JSON values are mapped to
151Perl.
152 145
153=back 146=back
154 147
155 148
156=head1 A FEW NOTES ON UNICODE AND PERL 149=head1 A FEW NOTES ON UNICODE AND PERL
411 [ 404 [
412 1, # this comment not allowed in JSON 405 1, # this comment not allowed in JSON
413 # neither this one... 406 # neither this one...
414 ] 407 ]
415 408
409=item * literal ASCII TAB characters in strings
410
411Literal ASCII TAB characters are now allowed in strings (and treated as
412C<\t>).
413
414 [
415 "Hello\tWorld",
416 "Hello<TAB>World", # literal <TAB> would not normally be allowed
417 ]
418
416=back 419=back
417 420
418=item $json = $json->canonical ([$enable]) 421=item $json = $json->canonical ([$enable])
419 422
420=item $enabled = $json->get_canonical 423=item $enabled = $json->get_canonical
474 477
475=item $json = $json->allow_blessed ([$enable]) 478=item $json = $json->allow_blessed ([$enable])
476 479
477=item $enabled = $json->get_allow_blessed 480=item $enabled = $json->get_allow_blessed
478 481
482See L<OBJECT SERIALISATION> for details.
483
479If C<$enable> is true (or missing), then the C<encode> method will not 484If C<$enable> is true (or missing), then the C<encode> method will not
480barf when it encounters a blessed reference. Instead, the value of the 485barf when it encounters a blessed reference that it cannot convert
481B<convert_blessed> option will decide whether C<null> (C<convert_blessed> 486otherwise. Instead, a JSON C<null> value is encoded instead of the object.
482disabled or no C<TO_JSON> method found) or a representation of the
483object (C<convert_blessed> enabled and C<TO_JSON> method found) is being
484encoded. Has no effect on C<decode>.
485 487
486If C<$enable> is false (the default), then C<encode> will throw an 488If C<$enable> is false (the default), then C<encode> will throw an
487exception when it encounters a blessed object. 489exception when it encounters a blessed object that it cannot convert
490otherwise.
491
492This setting has no effect on C<decode>.
488 493
489=item $json = $json->convert_blessed ([$enable]) 494=item $json = $json->convert_blessed ([$enable])
490 495
491=item $enabled = $json->get_convert_blessed 496=item $enabled = $json->get_convert_blessed
497
498See L<OBJECT SERIALISATION> for details.
492 499
493If C<$enable> is true (or missing), then C<encode>, upon encountering a 500If C<$enable> is true (or missing), then C<encode>, upon encountering a
494blessed object, will check for the availability of the C<TO_JSON> method 501blessed object, will check for the availability of the C<TO_JSON> method
495on the object's class. If found, it will be called in scalar context 502on the object's class. If found, it will be called in scalar context and
496and the resulting scalar will be encoded instead of the object. If no 503the resulting scalar will be encoded instead of the object.
497C<TO_JSON> method is found, the value of C<allow_blessed> will decide what
498to do.
499 504
500The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON> 505The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>
501returns other blessed objects, those will be handled in the same 506returns other blessed objects, those will be handled in the same
502way. C<TO_JSON> must take care of not causing an endless recursion cycle 507way. C<TO_JSON> must take care of not causing an endless recursion cycle
503(== crash) in this case. The name of C<TO_JSON> was chosen because other 508(== crash) in this case. The name of C<TO_JSON> was chosen because other
504methods called by the Perl core (== not by the user of the object) are 509methods called by the Perl core (== not by the user of the object) are
505usually in upper case letters and to avoid collisions with any C<to_json> 510usually in upper case letters and to avoid collisions with any C<to_json>
506function or method. 511function or method.
507 512
508This setting does not yet influence C<decode> in any way, but in the 513If C<$enable> is false (the default), then C<encode> will not consider
509future, global hooks might get installed that influence C<decode> and are 514this type of conversion.
510enabled by this setting.
511 515
512If C<$enable> is false, then the C<allow_blessed> setting will decide what 516This setting has no effect on C<decode>.
513to do when a blessed object is found. 517
518=item $json = $json->allow_tags ([$enable])
519
520=item $enabled = $json->allow_tags
521
522See L<OBJECT SERIALISATION> for details.
523
524If C<$enable> is true (or missing), then C<encode>, upon encountering a
525blessed object, will check for the availability of the C<FREEZE> method on
526the object's class. If found, it will be used to serialise the object into
527a nonstandard tagged JSON value (that JSON decoders cannot decode).
528
529It also causes C<decode> to parse such tagged JSON values and deserialise
530them via a call to the C<THAW> method.
531
532If C<$enable> is false (the default), then C<encode> will not consider
533this type of conversion, and tagged JSON values will cause a parse error
534in C<decode>, as if tags were not part of the grammar.
514 535
515=item $json = $json->filter_json_object ([$coderef->($hashref)]) 536=item $json = $json->filter_json_object ([$coderef->($hashref)])
516 537
517When C<$coderef> is specified, it will be called from C<decode> each 538When C<$coderef> is specified, it will be called from C<decode> each
518time it decodes a JSON object. The only argument is a reference to the 539time it decodes a JSON object. The only argument is a reference to the
676 697
677This is useful if your JSON texts are not delimited by an outer protocol 698This is useful if your JSON texts are not delimited by an outer protocol
678and you need to know where the JSON text ends. 699and you need to know where the JSON text ends.
679 700
680 JSON::XS->new->decode_prefix ("[1] the tail") 701 JSON::XS->new->decode_prefix ("[1] the tail")
681 => ([], 3) 702 => ([1], 3)
682 703
683=back 704=back
684 705
685 706
686=head1 INCREMENTAL PARSING 707=head1 INCREMENTAL PARSING
727C<incr_skip> to skip the erroneous part). This is the most common way of 748C<incr_skip> to skip the erroneous part). This is the most common way of
728using the method. 749using the method.
729 750
730And finally, in list context, it will try to extract as many objects 751And finally, in list context, it will try to extract as many objects
731from the stream as it can find and return them, or the empty list 752from the stream as it can find and return them, or the empty list
732otherwise. For this to work, there must be no separators between the JSON 753otherwise. For this to work, there must be no separators (other than
733objects or arrays, instead they must be concatenated back-to-back. If 754whitespace) between the JSON objects or arrays, instead they must be
734an error occurs, an exception will be raised as in the scalar context 755concatenated back-to-back. If an error occurs, an exception will be
735case. Note that in this case, any previously-parsed JSON texts will be 756raised as in the scalar context case. Note that in this case, any
736lost. 757previously-parsed JSON texts will be lost.
737 758
738Example: Parse some JSON arrays/objects in a given string and return 759Example: Parse some JSON arrays/objects in a given string and return
739them. 760them.
740 761
741 my @objs = JSON::XS->new->incr_parse ("[5][7][1,2]"); 762 my @objs = JSON::XS->new->incr_parse ("[5][7][1,2]");
983floating point, JSON::XS only guarantees precision up to but not including 1004floating point, JSON::XS only guarantees precision up to but not including
984the least significant bit. 1005the least significant bit.
985 1006
986=item true, false 1007=item true, false
987 1008
988These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, 1009These JSON atoms become C<Types::Serialiser::true> and
989respectively. They are overloaded to act almost exactly like the numbers 1010C<Types::Serialiser::false>, respectively. They are overloaded to act
990C<1> and C<0>. You can check whether a scalar is a JSON boolean by using 1011almost exactly like the numbers C<1> and C<0>. You can check whether
991the C<JSON::XS::is_bool> function. 1012a scalar is a JSON boolean by using the C<Types::Serialiser::is_bool>
1013function (after C<use Types::Serialier>, of course).
992 1014
993=item null 1015=item null
994 1016
995A JSON null atom becomes C<undef> in Perl. 1017A JSON null atom becomes C<undef> in Perl.
1018
1019=item shell-style comments (C<< # I<text> >>)
1020
1021As a nonstandard extension to the JSON syntax that is enabled by the
1022C<relaxed> setting, shell-style comments are allowed. They can start
1023anywhere outside strings and go till the end of the line.
1024
1025=item tagged values (C<< (I<tag>)I<value> >>).
1026
1027Another nonstandard extension to the JSON syntax, enabled with the
1028C<allow_tags> setting, are tagged values. In this implementation, the
1029I<tag> must be a perl package/class name encoded as a JSON string, and the
1030I<value> must be a JSON array encoding optional constructor arguments.
1031
1032See L<OBJECT SERIALISATION>, below, for details.
996 1033
997=back 1034=back
998 1035
999 1036
1000=head2 PERL -> JSON 1037=head2 PERL -> JSON
1021 1058
1022=item other references 1059=item other references
1023 1060
1024Other unblessed references are generally not allowed and will cause an 1061Other unblessed references are generally not allowed and will cause an
1025exception to be thrown, except for references to the integers C<0> and 1062exception to be thrown, except for references to the integers C<0> and
1026C<1>, which get turned into C<false> and C<true> atoms in JSON. You can 1063C<1>, which get turned into C<false> and C<true> atoms in JSON.
1027also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.
1028 1064
1065Since C<JSON::XS> uses the boolean model from L<Types::Serialiser>, you
1066can also C<use Types::Serialiser> and then use C<Types::Serialiser::false>
1067and C<Types::Serialiser::true> to improve readability.
1068
1069 use Types::Serialiser;
1029 encode_json [\0, JSON::XS::true] # yields [false,true] 1070 encode_json [\0, Types::Serialiser::true] # yields [false,true]
1030 1071
1031=item JSON::XS::true, JSON::XS::false 1072=item Types::Serialiser::true, Types::Serialiser::false
1032 1073
1033These special values become JSON true and JSON false values, 1074These special values from the L<Types::Serialiser> module become JSON true
1034respectively. You can also use C<\1> and C<\0> directly if you want. 1075and JSON false values, respectively. You can also use C<\1> and C<\0>
1076directly if you want.
1035 1077
1036=item blessed objects 1078=item blessed objects
1037 1079
1038Blessed objects are not directly representable in JSON. See the 1080Blessed objects are not directly representable in JSON, but C<JSON::XS>
1039C<allow_blessed> and C<convert_blessed> methods on various options on 1081allows various ways of handling objects. See L<OBJECT SERIALISATION>,
1040how to deal with this: basically, you can choose between throwing an 1082below, for details.
1041exception, encoding the reference as if it weren't blessed, or provide
1042your own serialiser method.
1043 1083
1044=item simple scalars 1084=item simple scalars
1045 1085
1046Simple Perl scalars (any scalar that is not a reference) are the most 1086Simple Perl scalars (any scalar that is not a reference) are the most
1047difficult objects to encode: JSON::XS will encode undefined scalars as 1087difficult objects to encode: JSON::XS will encode undefined scalars as
1083extensions to the floating point numbers of your platform, such as 1123extensions to the floating point numbers of your platform, such as
1084infinities or NaN's - these cannot be represented in JSON, and it is an 1124infinities or NaN's - these cannot be represented in JSON, and it is an
1085error to pass those in. 1125error to pass those in.
1086 1126
1087=back 1127=back
1128
1129=head2 OBJECT SERIALISATION
1130
1131As JSON cannot directly represent Perl objects, you have to choose between
1132a pure JSON representation (without the ability to deserialise the object
1133automatically again), and a nonstandard extension to the JSON syntax,
1134tagged values.
1135
1136=head3 SERIALISATION
1137
1138What happens when C<JSON::XS> encounters a Perl object depends on the
1139C<allow_blessed>, C<convert_blessed> and C<allow_tags> settings, which are
1140used in this order:
1141
1142=over 4
1143
1144=item 1. C<allow_tags> is enabled and the object has a C<FREEZE> method.
1145
1146In this case, C<JSON::XS> uses the L<Types::Serialiser> object
1147serialisation protocol to create a tagged JSON value, using a nonstandard
1148extension to the JSON syntax.
1149
1150This works by invoking the C<FREEZE> method on the object, with the first
1151argument being the object to serialise, and the second argument being the
1152constant string C<JSON> to distinguish it from other serialisers.
1153
1154The C<FREEZE> method can return any number of values (i.e. zero or
1155more). These values and the paclkage/classname of the object will then be
1156encoded as a tagged JSON value in the following format:
1157
1158 ("classname")[FREEZE return values...]
1159
1160e.g.:
1161
1162 ("URI")["http://www.google.com/"]
1163 ("MyDate")[2013,10,29]
1164 ("ImageData::JPEG")["Z3...VlCg=="]
1165
1166For example, the hypothetical C<My::Object> C<FREEZE> method might use the
1167objects C<type> and C<id> members to encode the object:
1168
1169 sub My::Object::FREEZE {
1170 my ($self, $serialiser) = @_;
1171
1172 ($self->{type}, $self->{id})
1173 }
1174
1175=item 2. C<convert_blessed> is enabled and the object has a C<TO_JSON> method.
1176
1177In this case, the C<TO_JSON> method of the object is invoked in scalar
1178context. It must return a single scalar that can be directly encoded into
1179JSON. This scalar replaces the object in the JSON text.
1180
1181For example, the following C<TO_JSON> method will convert all L<URI>
1182objects to JSON strings when serialised. The fatc that these values
1183originally were L<URI> objects is lost.
1184
1185 sub URI::TO_JSON {
1186 my ($uri) = @_;
1187 $uri->as_string
1188 }
1189
1190=item 3. C<allow_blessed> is enabled.
1191
1192The object will be serialised as a JSON null value.
1193
1194=item 4. none of the above
1195
1196If none of the settings are enabled or the respective methods are missing,
1197C<JSON::XS> throws an exception.
1198
1199=back
1200
1201=head3 DESERIALISATION
1202
1203For deserialisation there are only two cases to consider: either
1204nonstandard tagging was used, in which case C<allow_tags> decides,
1205or objects cannot be automatically be deserialised, in which
1206case you can use postprocessing or the C<filter_json_object> or
1207C<filter_json_single_key_object> callbacks to get some real objects our of
1208your JSON.
1209
1210This section only considers the tagged value case: I a tagged JSON object
1211is encountered during decoding and C<allow_tags> is disabled, a parse
1212error will result (as if tagged values were not part of the grammar).
1213
1214If C<allow_tags> is enabled, C<JSON::XS> will look up the C<THAW> method
1215of the package/classname used during serialisation (it will not attempt
1216to load the package as a Perl module). If there is no such method, the
1217decoding will fail with an error.
1218
1219Otherwise, the C<THAW> method is invoked with the classname as first
1220argument, the constant string C<JSON> as second argument, and all the
1221values from the JSON array (the values originally returned by the
1222C<FREEZE> method) as remaining arguments.
1223
1224The method must then return the object. While technically you can return
1225any Perl scalar, you might have to enable the C<enable_nonref> setting to
1226make that work in all cases, so better return an actual blessed reference.
1227
1228As an example, let's implement a C<THAW> function that regenerates the
1229C<My::Object> from the C<FREEZE> example earlier:
1230
1231 sub My::Object::THAW {
1232 my ($class, $serialiser, $type, $id) = @_;
1233
1234 $class->new (type => $type, id => $id)
1235 }
1088 1236
1089 1237
1090=head1 ENCODING/CODESET FLAG NOTES 1238=head1 ENCODING/CODESET FLAG NOTES
1091 1239
1092The interested reader might have seen a number of flags that signify 1240The interested reader might have seen a number of flags that signify
1415are browser design bugs, but it is still you who will have to deal with 1563are browser design bugs, but it is still you who will have to deal with
1416it, as major browser developers care only for features, not about getting 1564it, as major browser developers care only for features, not about getting
1417security right). 1565security right).
1418 1566
1419 1567
1568=head1 "OLD" VS. "NEW" JSON (RFC 4627 VS. RFC 7159)
1569
1570TL;DR: Due to security concerns, JSON::XS will not allow scalar data in
1571JSON texts by default - you need to create your own JSON::XS object and
1572enable C<allow_nonref>:
1573
1574
1575 my $json = JSON::XS->new->allow_nonref;
1576
1577 $text = $json->encode ($data);
1578 $data = $json->decode ($text);
1579
1580The long version: JSON being an important and supposedly stable format,
1581the IETF standardised it as RFC 4627 in 2006. Unfortunately, the inventor
1582of JSON, Dougles Crockford, unilaterally changed the definition of JSON in
1583javascript. Rather than create a fork, the IETF decided to standardise the
1584new syntax (apparently, so Iw as told, without finding it very amusing).
1585
1586The biggest difference between thed original JSON and the new JSON is that
1587the new JSON supports scalars (anything other than arrays and objects) at
1588the toplevel of a JSON text. While this is strictly backwards compatible
1589to older versions, it breaks a number of protocols that relied on sending
1590JSON back-to-back, and is a minor security concern.
1591
1592For example, imagine you have two banks communicating, and on one side,
1593trhe JSON coder gets upgraded. Two messages, such as C<10> and C<1000>
1594might then be confused to mean C<101000>, something that couldn't happen
1595in the original JSON, because niether of these messages would be valid
1596JSON.
1597
1598If one side accepts these messages, then an upgrade in the coder on either
1599side could result in this becoming exploitable.
1600
1601This module has always allowed these messages as an optional extension, by
1602default disabled. The security concerns are the reason why the default is
1603still disabled, but future versions might/will likely upgrade to the newer
1604RFC as default format, so you are advised to check your implementation
1605and/or override the default with C<< ->allow_nonref (0) >> to ensure that
1606future versions are safe.
1607
1608
1609=head1 INTEROPERABILITY WITH OTHER MODULES
1610
1611C<JSON::XS> uses the L<Types::Serialiser> module to provide boolean
1612constants. That means that the JSON true and false values will be
1613comaptible to true and false values of other modules that do the same,
1614such as L<JSON::PP> and L<CBOR::XS>.
1615
1616
1617=head1 INTEROPERABILITY WITH OTHER JSON DECODERS
1618
1619As long as you only serialise data that can be directly expressed in JSON,
1620C<JSON::XS> is incapable of generating invalid JSON output (modulo bugs,
1621but C<JSON::XS> has found more bugs in the official JSON testsuite (1)
1622than the official JSON testsuite has found in C<JSON::XS> (0)).
1623
1624When you have trouble decoding JSON generated by this module using other
1625decoders, then it is very likely that you have an encoding mismatch or the
1626other decoder is broken.
1627
1628When decoding, C<JSON::XS> is strict by default and will likely catch all
1629errors. There are currently two settings that change this: C<relaxed>
1630makes C<JSON::XS> accept (but not generate) some non-standard extensions,
1631and C<allow_tags> will allow you to encode and decode Perl objects, at the
1632cost of not outputting valid JSON anymore.
1633
1634=head2 TAGGED VALUE SYNTAX AND STANDARD JSON EN/DECODERS
1635
1636When you use C<allow_tags> to use the extended (and also nonstandard and
1637invalid) JSON syntax for serialised objects, and you still want to decode
1638the generated When you want to serialise objects, you can run a regex
1639to replace the tagged syntax by standard JSON arrays (it only works for
1640"normal" package names without comma, newlines or single colons). First,
1641the readable Perl version:
1642
1643 # if your FREEZE methods return no values, you need this replace first:
1644 $json =~ s/\( \s* (" (?: [^\\":,]+|\\.|::)* ") \s* \) \s* \[\s*\]/[$1]/gx;
1645
1646 # this works for non-empty constructor arg lists:
1647 $json =~ s/\( \s* (" (?: [^\\":,]+|\\.|::)* ") \s* \) \s* \[/[$1,/gx;
1648
1649And here is a less readable version that is easy to adapt to other
1650languages:
1651
1652 $json =~ s/\(\s*("([^\\":,]+|\\.|::)*")\s*\)\s*\[/[$1,/g;
1653
1654Here is an ECMAScript version (same regex):
1655
1656 json = json.replace (/\(\s*("([^\\":,]+|\\.|::)*")\s*\)\s*\[/g, "[$1,");
1657
1658Since this syntax converts to standard JSON arrays, it might be hard to
1659distinguish serialised objects from normal arrays. You can prepend a
1660"magic number" as first array element to reduce chances of a collision:
1661
1662 $json =~ s/\(\s*("([^\\":,]+|\\.|::)*")\s*\)\s*\[/["XU1peReLzT4ggEllLanBYq4G9VzliwKF",$1,/g;
1663
1664And after decoding the JSON text, you could walk the data
1665structure looking for arrays with a first element of
1666C<XU1peReLzT4ggEllLanBYq4G9VzliwKF>.
1667
1668The same approach can be used to create the tagged format with another
1669encoder. First, you create an array with the magic string as first member,
1670the classname as second, and constructor arguments last, encode it as part
1671of your JSON structure, and then:
1672
1673 $json =~ s/\[\s*"XU1peReLzT4ggEllLanBYq4G9VzliwKF"\s*,\s*("([^\\":,]+|\\.|::)*")\s*,/($1)[/g;
1674
1675Again, this has some limitations - the magic string must not be encoded
1676with character escapes, and the constructor arguments must be non-empty.
1677
1678
1679=head1 RFC7159
1680
1681Since this module was written, Google has written a new JSON RFC, RFC 7159
1682(and RFC7158). Unfortunately, this RFC breaks compatibility with both the
1683original JSON specification on www.json.org and RFC4627.
1684
1685As far as I can see, you can get partial compatibility when parsing by
1686using C<< ->allow_nonref >>. However, consider the security implications
1687of doing so.
1688
1689I haven't decided yet when to break compatibility with RFC4627 by default
1690(and potentially leave applications insecure) and change the default to
1691follow RFC7159, but application authors are well advised to call C<<
1692->allow_nonref(0) >> even if this is the current default, if they cannot
1693handle non-reference values, in preparation for the day when the default
1694will change.
1695
1696
1420=head1 THREADS 1697=head1 THREADS
1421 1698
1422This module is I<not> guaranteed to be thread safe and there are no 1699This module is I<not> guaranteed to be thread safe and there are no
1423plans to change this until Perl gets thread support (as opposed to the 1700plans to change this until Perl gets thread support (as opposed to the
1424horribly slow so-called "threads" which are simply slow and bloated 1701horribly slow so-called "threads" which are simply slow and bloated
1454Please refrain from using rt.cpan.org or any other bug reporting 1731Please refrain from using rt.cpan.org or any other bug reporting
1455service. I put the contact address into my modules for a reason. 1732service. I put the contact address into my modules for a reason.
1456 1733
1457=cut 1734=cut
1458 1735
1459our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" }; 1736BEGIN {
1460our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" }; 1737 *true = \$Types::Serialiser::true;
1738 *true = \&Types::Serialiser::true;
1739 *false = \$Types::Serialiser::false;
1740 *false = \&Types::Serialiser::false;
1741 *is_bool = \&Types::Serialiser::is_bool;
1461 1742
1462sub true() { $true } 1743 *JSON::XS::Boolean:: = *Types::Serialiser::Boolean::;
1463sub false() { $false }
1464
1465sub is_bool($) {
1466 UNIVERSAL::isa $_[0], "JSON::XS::Boolean"
1467# or UNIVERSAL::isa $_[0], "JSON::Literal"
1468} 1744}
1469 1745
1470XSLoader::load "JSON::XS", $VERSION; 1746XSLoader::load "JSON::XS", $VERSION;
1471
1472package JSON::XS::Boolean;
1473
1474use overload
1475 "0+" => sub { ${$_[0]} },
1476 "++" => sub { $_[0] = ${$_[0]} + 1 },
1477 "--" => sub { $_[0] = ${$_[0]} - 1 },
1478 fallback => 1;
1479
14801;
1481 1747
1482=head1 SEE ALSO 1748=head1 SEE ALSO
1483 1749
1484The F<json_xs> command line utility for quick experiments. 1750The F<json_xs> command line utility for quick experiments.
1485 1751
1488 Marc Lehmann <schmorp@schmorp.de> 1754 Marc Lehmann <schmorp@schmorp.de>
1489 http://home.schmorp.de/ 1755 http://home.schmorp.de/
1490 1756
1491=cut 1757=cut
1492 1758
17591
1760

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