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Revision 1.139 by root, Thu May 23 09:31:32 2013 UTC vs.
Revision 1.151 by root, Tue Oct 29 15:55:49 2013 UTC

83this module usually compares favourably in terms of speed, too. 83this module usually compares favourably in terms of speed, too.
84 84
85=item * simple to use 85=item * simple to use
86 86
87This module has both a simple functional interface as well as an object 87This module has both a simple functional interface as well as an object
88oriented interface interface. 88oriented interface.
89 89
90=item * reasonably versatile output formats 90=item * reasonably versatile output formats
91 91
92You can choose between the most compact guaranteed-single-line format 92You can choose between the most compact guaranteed-single-line format
93possible (nice for simple line-based protocols), a pure-ASCII format 93possible (nice for simple line-based protocols), a pure-ASCII format
101 101
102package JSON::XS; 102package JSON::XS;
103 103
104use common::sense; 104use common::sense;
105 105
106our $VERSION = 2.34; 106our $VERSION = 3.01;
107our @ISA = qw(Exporter); 107our @ISA = qw(Exporter);
108 108
109our @EXPORT = qw(encode_json decode_json to_json from_json); 109our @EXPORT = qw(encode_json decode_json);
110
111sub to_json($) {
112 require Carp;
113 Carp::croak ("JSON::XS::to_json has been renamed to encode_json, either downgrade to pre-2.0 versions of JSON::XS or rename the call");
114}
115
116sub from_json($) {
117 require Carp;
118 Carp::croak ("JSON::XS::from_json has been renamed to decode_json, either downgrade to pre-2.0 versions of JSON::XS or rename the call");
119}
120 110
121use Exporter; 111use Exporter;
122use XSLoader; 112use XSLoader;
113
114use Types::Serialiser ();
123 115
124=head1 FUNCTIONAL INTERFACE 116=head1 FUNCTIONAL INTERFACE
125 117
126The following convenience methods are provided by this module. They are 118The following convenience methods are provided by this module. They are
127exported by default: 119exported by default:
148This function call is functionally identical to: 140This function call is functionally identical to:
149 141
150 $perl_scalar = JSON::XS->new->utf8->decode ($json_text) 142 $perl_scalar = JSON::XS->new->utf8->decode ($json_text)
151 143
152Except being faster. 144Except being faster.
153
154=item $is_boolean = JSON::XS::is_bool $scalar
155
156Returns true if the passed scalar represents either JSON::XS::true or
157JSON::XS::false, two constants that act like C<1> and C<0>, respectively
158and are used to represent JSON C<true> and C<false> values in Perl.
159
160See MAPPING, below, for more information on how JSON values are mapped to
161Perl.
162 145
163=back 146=back
164 147
165 148
166=head1 A FEW NOTES ON UNICODE AND PERL 149=head1 A FEW NOTES ON UNICODE AND PERL
484 467
485=item $json = $json->allow_blessed ([$enable]) 468=item $json = $json->allow_blessed ([$enable])
486 469
487=item $enabled = $json->get_allow_blessed 470=item $enabled = $json->get_allow_blessed
488 471
472See L<OBJECT SERIALISATION> for details.
473
489If C<$enable> is true (or missing), then the C<encode> method will not 474If C<$enable> is true (or missing), then the C<encode> method will not
490barf when it encounters a blessed reference. Instead, the value of the 475barf when it encounters a blessed reference that it cannot convert
491B<convert_blessed> option will decide whether C<null> (C<convert_blessed> 476otherwise. Instead, a JSON C<null> value is encoded instead of the object.
492disabled or no C<TO_JSON> method found) or a representation of the
493object (C<convert_blessed> enabled and C<TO_JSON> method found) is being
494encoded. Has no effect on C<decode>.
495 477
496If C<$enable> is false (the default), then C<encode> will throw an 478If C<$enable> is false (the default), then C<encode> will throw an
497exception when it encounters a blessed object. 479exception when it encounters a blessed object that it cannot convert
480otherwise.
481
482This setting has no effect on C<decode>.
498 483
499=item $json = $json->convert_blessed ([$enable]) 484=item $json = $json->convert_blessed ([$enable])
500 485
501=item $enabled = $json->get_convert_blessed 486=item $enabled = $json->get_convert_blessed
487
488See L<OBJECT SERIALISATION> for details.
502 489
503If C<$enable> is true (or missing), then C<encode>, upon encountering a 490If C<$enable> is true (or missing), then C<encode>, upon encountering a
504blessed object, will check for the availability of the C<TO_JSON> method 491blessed object, will check for the availability of the C<TO_JSON> method
505on the object's class. If found, it will be called in scalar context 492on the object's class. If found, it will be called in scalar context and
506and the resulting scalar will be encoded instead of the object. If no 493the resulting scalar will be encoded instead of the object.
507C<TO_JSON> method is found, the value of C<allow_blessed> will decide what
508to do.
509 494
510The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON> 495The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>
511returns other blessed objects, those will be handled in the same 496returns other blessed objects, those will be handled in the same
512way. C<TO_JSON> must take care of not causing an endless recursion cycle 497way. C<TO_JSON> must take care of not causing an endless recursion cycle
513(== crash) in this case. The name of C<TO_JSON> was chosen because other 498(== crash) in this case. The name of C<TO_JSON> was chosen because other
514methods called by the Perl core (== not by the user of the object) are 499methods called by the Perl core (== not by the user of the object) are
515usually in upper case letters and to avoid collisions with any C<to_json> 500usually in upper case letters and to avoid collisions with any C<to_json>
516function or method. 501function or method.
517 502
518This setting does not yet influence C<decode> in any way, but in the 503If C<$enable> is false (the default), then C<encode> will not consider
519future, global hooks might get installed that influence C<decode> and are 504this type of conversion.
520enabled by this setting.
521 505
522If C<$enable> is false, then the C<allow_blessed> setting will decide what 506This setting has no effect on C<decode>.
523to do when a blessed object is found. 507
508=item $json = $json->allow_tags ([$enable])
509
510=item $enabled = $json->allow_tags
511
512See L<OBJECT SERIALISATION> for details.
513
514If C<$enable> is true (or missing), then C<encode>, upon encountering a
515blessed object, will check for the availability of the C<FREEZE> method on
516the object's class. If found, it will be used to serialise the object into
517a nonstandard tagged JSON value (that JSON decoders cannot decode).
518
519It also causes C<decode> to parse such tagged JSON values and deserialise
520them via a call to the C<THAW> method.
521
522If C<$enable> is false (the default), then C<encode> will not consider
523this type of conversion, and tagged JSON values will cause a parse error
524in C<decode>, as if tags were not part of the grammar.
524 525
525=item $json = $json->filter_json_object ([$coderef->($hashref)]) 526=item $json = $json->filter_json_object ([$coderef->($hashref)])
526 527
527When C<$coderef> is specified, it will be called from C<decode> each 528When C<$coderef> is specified, it will be called from C<decode> each
528time it decodes a JSON object. The only argument is a reference to the 529time it decodes a JSON object. The only argument is a reference to the
667 668
668See SECURITY CONSIDERATIONS, below, for more info on why this is useful. 669See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
669 670
670=item $json_text = $json->encode ($perl_scalar) 671=item $json_text = $json->encode ($perl_scalar)
671 672
672Converts the given Perl data structure (a simple scalar or a reference 673Converts the given Perl value or data structure to its JSON
673to a hash or array) to its JSON representation. Simple scalars will be 674representation. Croaks on error.
674converted into JSON string or number sequences, while references to arrays
675become JSON arrays and references to hashes become JSON objects. Undefined
676Perl values (e.g. C<undef>) become JSON C<null> values. Neither C<true>
677nor C<false> values will be generated.
678 675
679=item $perl_scalar = $json->decode ($json_text) 676=item $perl_scalar = $json->decode ($json_text)
680 677
681The opposite of C<encode>: expects a JSON text and tries to parse it, 678The opposite of C<encode>: expects a JSON text and tries to parse it,
682returning the resulting simple scalar or reference. Croaks on error. 679returning the resulting simple scalar or reference. Croaks on error.
683
684JSON numbers and strings become simple Perl scalars. JSON arrays become
685Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes
686C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.
687 680
688=item ($perl_scalar, $characters) = $json->decode_prefix ($json_text) 681=item ($perl_scalar, $characters) = $json->decode_prefix ($json_text)
689 682
690This works like the C<decode> method, but instead of raising an exception 683This works like the C<decode> method, but instead of raising an exception
691when there is trailing garbage after the first JSON object, it will 684when there is trailing garbage after the first JSON object, it will
692silently stop parsing there and return the number of characters consumed 685silently stop parsing there and return the number of characters consumed
693so far. 686so far.
694 687
695This is useful if your JSON texts are not delimited by an outer protocol 688This is useful if your JSON texts are not delimited by an outer protocol
696(which is not the brightest thing to do in the first place) and you need
697to know where the JSON text ends. 689and you need to know where the JSON text ends.
698 690
699 JSON::XS->new->decode_prefix ("[1] the tail") 691 JSON::XS->new->decode_prefix ("[1] the tail")
700 => ([], 3) 692 => ([], 3)
701 693
702=back 694=back
741 733
742If the method is called in scalar context, then it will try to extract 734If the method is called in scalar context, then it will try to extract
743exactly I<one> JSON object. If that is successful, it will return this 735exactly I<one> JSON object. If that is successful, it will return this
744object, otherwise it will return C<undef>. If there is a parse error, 736object, otherwise it will return C<undef>. If there is a parse error,
745this method will croak just as C<decode> would do (one can then use 737this method will croak just as C<decode> would do (one can then use
746C<incr_skip> to skip the errornous part). This is the most common way of 738C<incr_skip> to skip the erroneous part). This is the most common way of
747using the method. 739using the method.
748 740
749And finally, in list context, it will try to extract as many objects 741And finally, in list context, it will try to extract as many objects
750from the stream as it can find and return them, or the empty list 742from the stream as it can find and return them, or the empty list
751otherwise. For this to work, there must be no separators between the JSON 743otherwise. For this to work, there must be no separators between the JSON
780C<incr_parse> died, in which case the input buffer and incremental parser 772C<incr_parse> died, in which case the input buffer and incremental parser
781state is left unchanged, to skip the text parsed so far and to reset the 773state is left unchanged, to skip the text parsed so far and to reset the
782parse state. 774parse state.
783 775
784The difference to C<incr_reset> is that only text until the parse error 776The difference to C<incr_reset> is that only text until the parse error
785occured is removed. 777occurred is removed.
786 778
787=item $json->incr_reset 779=item $json->incr_reset
788 780
789This completely resets the incremental parser, that is, after this call, 781This completely resets the incremental parser, that is, after this call,
790it will be as if the parser had never parsed anything. 782it will be as if the parser had never parsed anything.
796=back 788=back
797 789
798=head2 LIMITATIONS 790=head2 LIMITATIONS
799 791
800All options that affect decoding are supported, except 792All options that affect decoding are supported, except
801C<allow_nonref>. The reason for this is that it cannot be made to 793C<allow_nonref>. The reason for this is that it cannot be made to work
802work sensibly: JSON objects and arrays are self-delimited, i.e. you can concatenate 794sensibly: JSON objects and arrays are self-delimited, i.e. you can
803them back to back and still decode them perfectly. This does not hold true 795concatenate them back to back and still decode them perfectly. This does
804for JSON numbers, however. 796not hold true for JSON numbers, however.
805 797
806For example, is the string C<1> a single JSON number, or is it simply the 798For example, is the string C<1> a single JSON number, or is it simply the
807start of C<12>? Or is C<12> a single JSON number, or the concatenation 799start of C<12>? Or is C<12> a single JSON number, or the concatenation
808of C<1> and C<2>? In neither case you can tell, and this is why JSON::XS 800of C<1> and C<2>? In neither case you can tell, and this is why JSON::XS
809takes the conservative route and disallows this case. 801takes the conservative route and disallows this case.
988If the number consists of digits only, JSON::XS will try to represent 980If the number consists of digits only, JSON::XS will try to represent
989it as an integer value. If that fails, it will try to represent it as 981it as an integer value. If that fails, it will try to represent it as
990a numeric (floating point) value if that is possible without loss of 982a numeric (floating point) value if that is possible without loss of
991precision. Otherwise it will preserve the number as a string value (in 983precision. Otherwise it will preserve the number as a string value (in
992which case you lose roundtripping ability, as the JSON number will be 984which case you lose roundtripping ability, as the JSON number will be
993re-encoded toa JSON string). 985re-encoded to a JSON string).
994 986
995Numbers containing a fractional or exponential part will always be 987Numbers containing a fractional or exponential part will always be
996represented as numeric (floating point) values, possibly at a loss of 988represented as numeric (floating point) values, possibly at a loss of
997precision (in which case you might lose perfect roundtripping ability, but 989precision (in which case you might lose perfect roundtripping ability, but
998the JSON number will still be re-encoded as a JSON number). 990the JSON number will still be re-encoded as a JSON number).
999 991
1000Note that precision is not accuracy - binary floating point values cannot 992Note that precision is not accuracy - binary floating point values cannot
1001represent most decimal fractions exactly, and when converting from and to 993represent most decimal fractions exactly, and when converting from and to
1002floating point, JSON::XS only guarantees precision up to but not including 994floating point, JSON::XS only guarantees precision up to but not including
1003the leats significant bit. 995the least significant bit.
1004 996
1005=item true, false 997=item true, false
1006 998
1007These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, 999These JSON atoms become C<Types::Serialiser::true> and
1008respectively. They are overloaded to act almost exactly like the numbers 1000C<Types::Serialiser::false>, respectively. They are overloaded to act
1009C<1> and C<0>. You can check whether a scalar is a JSON boolean by using 1001almost exactly like the numbers C<1> and C<0>. You can check whether
1010the C<JSON::XS::is_bool> function. 1002a scalar is a JSON boolean by using the C<Types::Serialiser::is_bool>
1003function (after C<use Types::Serialier>, of course).
1011 1004
1012=item null 1005=item null
1013 1006
1014A JSON null atom becomes C<undef> in Perl. 1007A JSON null atom becomes C<undef> in Perl.
1008
1009=item shell-style comments (C<< # I<text> >>)
1010
1011As a nonstandard extension to the JSON syntax that is enabled by the
1012C<relaxed> setting, shell-style comments are allowed. They can start
1013anywhere outside strings and go till the end of the line.
1014
1015=item tagged values (C<< (I<tag>)I<value> >>).
1016
1017Another nonstandard extension to the JSON syntax, enabled with the
1018C<allow_tags> setting, are tagged values. In this implementation, the
1019I<tag> must be a perl package/class name encoded as a JSON string, and the
1020I<value> must be a JSON array encoding optional constructor arguments.
1021
1022See L<OBJECT SERIALISATION>, below, for details.
1015 1023
1016=back 1024=back
1017 1025
1018 1026
1019=head2 PERL -> JSON 1027=head2 PERL -> JSON
1024 1032
1025=over 4 1033=over 4
1026 1034
1027=item hash references 1035=item hash references
1028 1036
1029Perl hash references become JSON objects. As there is no inherent ordering 1037Perl hash references become JSON objects. As there is no inherent
1030in hash keys (or JSON objects), they will usually be encoded in a 1038ordering in hash keys (or JSON objects), they will usually be encoded
1031pseudo-random order that can change between runs of the same program but 1039in a pseudo-random order. JSON::XS can optionally sort the hash keys
1032stays generally the same within a single run of a program. JSON::XS can 1040(determined by the I<canonical> flag), so the same datastructure will
1033optionally sort the hash keys (determined by the I<canonical> flag), so 1041serialise to the same JSON text (given same settings and version of
1034the same datastructure will serialise to the same JSON text (given same 1042JSON::XS), but this incurs a runtime overhead and is only rarely useful,
1035settings and version of JSON::XS), but this incurs a runtime overhead 1043e.g. when you want to compare some JSON text against another for equality.
1036and is only rarely useful, e.g. when you want to compare some JSON text
1037against another for equality.
1038 1044
1039=item array references 1045=item array references
1040 1046
1041Perl array references become JSON arrays. 1047Perl array references become JSON arrays.
1042 1048
1043=item other references 1049=item other references
1044 1050
1045Other unblessed references are generally not allowed and will cause an 1051Other unblessed references are generally not allowed and will cause an
1046exception to be thrown, except for references to the integers C<0> and 1052exception to be thrown, except for references to the integers C<0> and
1047C<1>, which get turned into C<false> and C<true> atoms in JSON. You can 1053C<1>, which get turned into C<false> and C<true> atoms in JSON.
1048also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.
1049 1054
1055Since C<JSON::XS> uses the boolean model from L<Types::Serialiser>, you
1056can also C<use Types::Serialiser> and then use C<Types::Serialiser::false>
1057and C<Types::Serialiser::true> to improve readability.
1058
1059 use Types::Serialiser;
1050 encode_json [\0, JSON::XS::true] # yields [false,true] 1060 encode_json [\0, Types::Serialiser::true] # yields [false,true]
1051 1061
1052=item JSON::XS::true, JSON::XS::false 1062=item Types::Serialiser::true, Types::Serialiser::false
1053 1063
1054These special values become JSON true and JSON false values, 1064These special values from the L<Types::Serialiser> module become JSON true
1055respectively. You can also use C<\1> and C<\0> directly if you want. 1065and JSON false values, respectively. You can also use C<\1> and C<\0>
1066directly if you want.
1056 1067
1057=item blessed objects 1068=item blessed objects
1058 1069
1059Blessed objects are not directly representable in JSON. See the 1070Blessed objects are not directly representable in JSON, but C<JSON::XS>
1060C<allow_blessed> and C<convert_blessed> methods on various options on 1071allows various ways of handling objects. See L<OBJECT SERIALISATION>,
1061how to deal with this: basically, you can choose between throwing an 1072below, for details.
1062exception, encoding the reference as if it weren't blessed, or provide
1063your own serialiser method.
1064 1073
1065=item simple scalars 1074=item simple scalars
1066 1075
1067Simple Perl scalars (any scalar that is not a reference) are the most 1076Simple Perl scalars (any scalar that is not a reference) are the most
1068difficult objects to encode: JSON::XS will encode undefined scalars as 1077difficult objects to encode: JSON::XS will encode undefined scalars as
1105infinities or NaN's - these cannot be represented in JSON, and it is an 1114infinities or NaN's - these cannot be represented in JSON, and it is an
1106error to pass those in. 1115error to pass those in.
1107 1116
1108=back 1117=back
1109 1118
1119=head2 OBJECT SERIALISATION
1120
1121As JSON cannot directly represent Perl objects, you have to choose between
1122a pure JSON representation (without the ability to deserialise the object
1123automatically again), and a nonstandard extension to the JSON syntax,
1124tagged values.
1125
1126=head3 SERIALISATION
1127
1128What happens when C<JSON::XS> encounters a Perl object depends on the
1129C<allow_blessed>, C<convert_blessed> and C<allow_tags> settings, which are
1130used in this order:
1131
1132=over 4
1133
1134=item 1. C<allow_tags> is enabled and the object has a C<FREEZE> method.
1135
1136In this case, C<JSON::XS> uses the L<Types::Serialiser> object
1137serialisation protocol to create a tagged JSON value, using a nonstandard
1138extension to the JSON syntax.
1139
1140This works by invoking the C<FREEZE> method on the object, with the first
1141argument being the object to serialise, and the second argument being the
1142constant string C<JSON> to distinguish it from other serialisers.
1143
1144The C<FREEZE> method can return any number of values (i.e. zero or
1145more). These values and the paclkage/classname of the object will then be
1146encoded as a tagged JSON value in the following format:
1147
1148 ("classname")[FREEZE return values...]
1149
1150e.g.:
1151
1152 ("URI")["http://www.google.com/"]
1153 ("MyDate")[2013,10,29]
1154 ("ImageData::JPEG")["Z3...VlCg=="]
1155
1156For example, the hypothetical C<My::Object> C<FREEZE> method might use the
1157objects C<type> and C<id> members to encode the object:
1158
1159 sub My::Object::FREEZE {
1160 my ($self, $serialiser) = @_;
1161
1162 ($self->{type}, $self->{id})
1163 }
1164
1165=item 2. C<convert_blessed> is enabled and the object has a C<TO_JSON> method.
1166
1167In this case, the C<TO_JSON> method of the object is invoked in scalar
1168context. It must return a single scalar that can be directly encoded into
1169JSON. This scalar replaces the object in the JSON text.
1170
1171For example, the following C<TO_JSON> method will convert all L<URI>
1172objects to JSON strings when serialised. The fatc that these values
1173originally were L<URI> objects is lost.
1174
1175 sub URI::TO_JSON {
1176 my ($uri) = @_;
1177 $uri->as_string
1178 }
1179
1180=item 3. C<allow_blessed> is enabled.
1181
1182The object will be serialised as a JSON null value.
1183
1184=item 4. none of the above
1185
1186If none of the settings are enabled or the respective methods are missing,
1187C<JSON::XS> throws an exception.
1188
1189=back
1190
1191=head3 DESERIALISATION
1192
1193For deserialisation there are only two cases to consider: either
1194nonstandard tagging was used, in which case C<allow_tags> decides,
1195or objects cannot be automatically be deserialised, in which
1196case you can use postprocessing or the C<filter_json_object> or
1197C<filter_json_single_key_object> callbacks to get some real objects our of
1198your JSON.
1199
1200This section only considers the tagged value case: I a tagged JSON object
1201is encountered during decoding and C<allow_tags> is disabled, a parse
1202error will result (as if tagged values were not part of the grammar).
1203
1204If C<allow_tags> is enabled, C<JSON::XS> will look up the C<THAW> method
1205of the package/classname used during serialisation (it will not attempt
1206to load the package as a Perl module). If there is no such method, the
1207decoding will fail with an error.
1208
1209Otherwise, the C<THAW> method is invoked with the classname as first
1210argument, the constant string C<JSON> as second argument, and all the
1211values from the JSON array (the values originally returned by the
1212C<FREEZE> method) as remaining arguments.
1213
1214The method must then return the object. While technically you can return
1215any Perl scalar, you might have to enable the C<enable_nonref> setting to
1216make that work in all cases, so better return an actual blessed reference.
1217
1218As an example, let's implement a C<THAW> function that regenerates the
1219C<My::Object> from the C<FREEZE> example earlier:
1220
1221 sub My::Object::THAW {
1222 my ($class, $serialiser, $type, $id) = @_;
1223
1224 $class->new (type => $type, id => $id)
1225 }
1226
1110 1227
1111=head1 ENCODING/CODESET FLAG NOTES 1228=head1 ENCODING/CODESET FLAG NOTES
1112 1229
1113The interested reader might have seen a number of flags that signify 1230The interested reader might have seen a number of flags that signify
1114encodings or codesets - C<utf8>, C<latin1> and C<ascii>. There seems to be 1231encodings or codesets - C<utf8>, C<latin1> and C<ascii>. There seems to be
1138=item C<utf8> flag disabled 1255=item C<utf8> flag disabled
1139 1256
1140When C<utf8> is disabled (the default), then C<encode>/C<decode> generate 1257When C<utf8> is disabled (the default), then C<encode>/C<decode> generate
1141and expect Unicode strings, that is, characters with high ordinal Unicode 1258and expect Unicode strings, that is, characters with high ordinal Unicode
1142values (> 255) will be encoded as such characters, and likewise such 1259values (> 255) will be encoded as such characters, and likewise such
1143characters are decoded as-is, no canges to them will be done, except 1260characters are decoded as-is, no changes to them will be done, except
1144"(re-)interpreting" them as Unicode codepoints or Unicode characters, 1261"(re-)interpreting" them as Unicode codepoints or Unicode characters,
1145respectively (to Perl, these are the same thing in strings unless you do 1262respectively (to Perl, these are the same thing in strings unless you do
1146funny/weird/dumb stuff). 1263funny/weird/dumb stuff).
1147 1264
1148This is useful when you want to do the encoding yourself (e.g. when you 1265This is useful when you want to do the encoding yourself (e.g. when you
1264output for these property strings, e.g.: 1381output for these property strings, e.g.:
1265 1382
1266 $json =~ s/"__proto__"\s*:/"__proto__renamed":/g; 1383 $json =~ s/"__proto__"\s*:/"__proto__renamed":/g;
1267 1384
1268This works because C<__proto__> is not valid outside of strings, so every 1385This works because C<__proto__> is not valid outside of strings, so every
1269occurence of C<"__proto__"\s*:> must be a string used as property name. 1386occurrence of C<"__proto__"\s*:> must be a string used as property name.
1270 1387
1271If you know of other incompatibilities, please let me know. 1388If you know of other incompatibilities, please let me know.
1272 1389
1273 1390
1274=head2 JSON and YAML 1391=head2 JSON and YAML
1436are browser design bugs, but it is still you who will have to deal with 1553are browser design bugs, but it is still you who will have to deal with
1437it, as major browser developers care only for features, not about getting 1554it, as major browser developers care only for features, not about getting
1438security right). 1555security right).
1439 1556
1440 1557
1558=head1 INTEROPERABILITY WITH OTHER MODULES
1559
1560C<JSON::XS> uses the L<Types::Serialiser> module to provide boolean
1561constants. That means that the JSON true and false values will be
1562comaptible to true and false values of iother modules that do the same,
1563such as L<JSON::PP> and L<CBOR::XS>.
1564
1565
1441=head1 THREADS 1566=head1 THREADS
1442 1567
1443This module is I<not> guaranteed to be thread safe and there are no 1568This module is I<not> guaranteed to be thread safe and there are no
1444plans to change this until Perl gets thread support (as opposed to the 1569plans to change this until Perl gets thread support (as opposed to the
1445horribly slow so-called "threads" which are simply slow and bloated 1570horribly slow so-called "threads" which are simply slow and bloated
1452 1577
1453Sometimes people avoid the Perl locale support and directly call the 1578Sometimes people avoid the Perl locale support and directly call the
1454system's setlocale function with C<LC_ALL>. 1579system's setlocale function with C<LC_ALL>.
1455 1580
1456This breaks both perl and modules such as JSON::XS, as stringification of 1581This breaks both perl and modules such as JSON::XS, as stringification of
1457numbers no longer works correcly (e.g. C<$x = 0.1; print "$x"+1> might 1582numbers no longer works correctly (e.g. C<$x = 0.1; print "$x"+1> might
1458print C<1>, and JSON::XS might output illegal JSON as JSON::XS relies on 1583print C<1>, and JSON::XS might output illegal JSON as JSON::XS relies on
1459perl to stringify numbers). 1584perl to stringify numbers).
1460 1585
1461The solution is simple: don't call C<setlocale>, or use it for only those 1586The solution is simple: don't call C<setlocale>, or use it for only those
1462categories you need, such as C<LC_MESSAGES> or C<LC_CTYPE>. 1587categories you need, such as C<LC_MESSAGES> or C<LC_CTYPE>.
1475Please refrain from using rt.cpan.org or any other bug reporting 1600Please refrain from using rt.cpan.org or any other bug reporting
1476service. I put the contact address into my modules for a reason. 1601service. I put the contact address into my modules for a reason.
1477 1602
1478=cut 1603=cut
1479 1604
1480our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" }; 1605BEGIN {
1481our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" }; 1606 *true = \$Types::Serialiser::true;
1607 *true = \&Types::Serialiser::true;
1608 *false = \$Types::Serialiser::false;
1609 *false = \&Types::Serialiser::false;
1610 *is_bool = \&Types::Serialiser::is_bool;
1482 1611
1483sub true() { $true } 1612 *JSON::XS::Boolean:: = *Types::Serialiser::Boolean::;
1484sub false() { $false }
1485
1486sub is_bool($) {
1487 UNIVERSAL::isa $_[0], "JSON::XS::Boolean"
1488# or UNIVERSAL::isa $_[0], "JSON::Literal"
1489} 1613}
1490 1614
1491XSLoader::load "JSON::XS", $VERSION; 1615XSLoader::load "JSON::XS", $VERSION;
1492
1493package JSON::XS::Boolean;
1494
1495use overload
1496 "0+" => sub { ${$_[0]} },
1497 "++" => sub { $_[0] = ${$_[0]} + 1 },
1498 "--" => sub { $_[0] = ${$_[0]} - 1 },
1499 fallback => 1;
1500
15011;
1502 1616
1503=head1 SEE ALSO 1617=head1 SEE ALSO
1504 1618
1505The F<json_xs> command line utility for quick experiments. 1619The F<json_xs> command line utility for quick experiments.
1506 1620
1509 Marc Lehmann <schmorp@schmorp.de> 1623 Marc Lehmann <schmorp@schmorp.de>
1510 http://home.schmorp.de/ 1624 http://home.schmorp.de/
1511 1625
1512=cut 1626=cut
1513 1627
16281
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