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Revision 1.130 by root, Thu Mar 11 17:36:09 2010 UTC vs.
Revision 1.134 by root, Mon Feb 21 15:38:06 2011 UTC

… …
64so, and even documents what "correct" means. 64so, and even documents what "correct" means.
65 65
66=item * round-trip integrity 66=item * round-trip integrity
67 67
68When you serialise a perl data structure using only data types supported 68When you serialise a perl data structure using only data types supported
69by JSON, the deserialised data structure is identical on the Perl level. 69by JSON and Perl, the deserialised data structure is identical on the Perl
70(e.g. the string "2.0" doesn't suddenly become "2" just because it looks 70level. (e.g. the string "2.0" doesn't suddenly become "2" just because
71like a number). There minor I<are> exceptions to this, read the MAPPING 71it looks like a number). There I<are> minor exceptions to this, read the
72section below to learn about those. 72MAPPING section below to learn about those.
73 73
74=item * strict checking of JSON correctness 74=item * strict checking of JSON correctness
75 75
76There is no guessing, no generating of illegal JSON texts by default, 76There is no guessing, no generating of illegal JSON texts by default,
77and only JSON is accepted as input by default (the latter is a security 77and only JSON is accepted as input by default (the latter is a security
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101 101
102package JSON::XS; 102package JSON::XS;
103 103
104use common::sense; 104use common::sense;
105 105
106our $VERSION = '2.28'; 106our $VERSION = '2.3';
107our @ISA = qw(Exporter); 107our @ISA = qw(Exporter);
108 108
109our @EXPORT = qw(encode_json decode_json to_json from_json); 109our @EXPORT = qw(encode_json decode_json to_json from_json);
110 110
111sub to_json($) { 111sub to_json($) {
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713calls). 713calls).
714 714
715JSON::XS will only attempt to parse the JSON text once it is sure it 715JSON::XS will only attempt to parse the JSON text once it is sure it
716has enough text to get a decisive result, using a very simple but 716has enough text to get a decisive result, using a very simple but
717truly incremental parser. This means that it sometimes won't stop as 717truly incremental parser. This means that it sometimes won't stop as
718early as the full parser, for example, it doesn't detect parenthese 718early as the full parser, for example, it doesn't detect mismatched
719mismatches. The only thing it guarantees is that it starts decoding as 719parentheses. The only thing it guarantees is that it starts decoding as
720soon as a syntactically valid JSON text has been seen. This means you need 720soon as a syntactically valid JSON text has been seen. This means you need
721to set resource limits (e.g. C<max_size>) to ensure the parser will stop 721to set resource limits (e.g. C<max_size>) to ensure the parser will stop
722parsing in the presence if syntax errors. 722parsing in the presence if syntax errors.
723 723
724The following methods implement this incremental parser. 724The following methods implement this incremental parser.
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994Numbers containing a fractional or exponential part will always be 994Numbers containing a fractional or exponential part will always be
995represented as numeric (floating point) values, possibly at a loss of 995represented as numeric (floating point) values, possibly at a loss of
996precision (in which case you might lose perfect roundtripping ability, but 996precision (in which case you might lose perfect roundtripping ability, but
997the JSON number will still be re-encoded as a JSON number). 997the JSON number will still be re-encoded as a JSON number).
998 998
999Note that precision is not accuracy - binary floating point values cannot
1000represent most decimal fractions exactly, and when converting from and to
1001floating point, JSON::XS only guarantees precision up to but not including
1002the leats significant bit.
1003
999=item true, false 1004=item true, false
1000 1005
1001These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, 1006These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>,
1002respectively. They are overloaded to act almost exactly like the numbers 1007respectively. They are overloaded to act almost exactly like the numbers
1003C<1> and C<0>. You can check whether a scalar is a JSON boolean by using 1008C<1> and C<0>. You can check whether a scalar is a JSON boolean by using
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1090 1095
1091You can not currently force the type in other, less obscure, ways. Tell me 1096You can not currently force the type in other, less obscure, ways. Tell me
1092if you need this capability (but don't forget to explain why it's needed 1097if you need this capability (but don't forget to explain why it's needed
1093:). 1098:).
1094 1099
1100Note that numerical precision has the same meaning as under Perl (so
1101binary to decimal conversion follows the same rules as in Perl, which
1102can differ to other languages). Also, your perl interpreter might expose
1103extensions to the floating point numbers of your platform, such as
1104infinities or NaN's - these cannot be represented in JSON, and it is an
1105error to pass those in.
1106
1095=back 1107=back
1096 1108
1097 1109
1098=head1 ENCODING/CODESET FLAG NOTES 1110=head1 ENCODING/CODESET FLAG NOTES
1099 1111
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1243well - using C<eval> naively simply I<will> cause problems. 1255well - using C<eval> naively simply I<will> cause problems.
1244 1256
1245Another problem is that some javascript implementations reserve 1257Another problem is that some javascript implementations reserve
1246some property names for their own purposes (which probably makes 1258some property names for their own purposes (which probably makes
1247them non-ECMAscript-compliant). For example, Iceweasel reserves the 1259them non-ECMAscript-compliant). For example, Iceweasel reserves the
1248C<__proto__> property name for it's own purposes. 1260C<__proto__> property name for its own purposes.
1249 1261
1250If that is a problem, you could parse try to filter the resulting JSON 1262If that is a problem, you could parse try to filter the resulting JSON
1251output for these property strings, e.g.: 1263output for these property strings, e.g.:
1252 1264
1253 $json =~ s/"__proto__"\s*:/"__proto__renamed":/g; 1265 $json =~ s/"__proto__"\s*:/"__proto__renamed":/g;

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