[ViewVC] Diff of: cvs/JSON-XS/XS.pm

Comparing JSON-XS/XS.pm (file contents):
Revision 1.130 by root, Thu Mar 11 17:36:09 2010 UTC vs.
Revision 1.139 by root, Thu May 23 09:31:32 2013 UTC

 so, and even documents what "correct" means.
 =item * round-trip integrity
 When you serialise a perl data structure using only data types supported
-by JSON, the deserialised data structure is identical on the Perl level.
+by JSON and Perl, the deserialised data structure is identical on the Perl
-(e.g. the string "2.0" doesn't suddenly become "2" just because it looks
+level. (e.g. the string "2.0" doesn't suddenly become "2" just because
-like a number). There minor I<are> exceptions to this, read the MAPPING
+it looks like a number). There I<are> minor exceptions to this, read the
-section below to learn about those.
+MAPPING section below to learn about those.
 =item * strict checking of JSON correctness
 There is no guessing, no generating of illegal JSON texts by default,
 and only JSON is accepted as input by default (the latter is a security
 package JSON::XS;
 use common::sense;
-our $VERSION = '2.28';
+our $VERSION = 2.34;
 our @ISA = qw(Exporter);
 our @EXPORT = qw(encode_json decode_json to_json from_json);
 sub to_json($) {
 If C<$enable> is true (or missing), then the C<encode> method will output JSON objects
 by sorting their keys. This is adding a comparatively high overhead.
 If C<$enable> is false, then the C<encode> method will output key-value
 pairs in the order Perl stores them (which will likely change between runs
-of the same script).
+of the same script, and can change even within the same run from 5.18
+onwards).
 This option is useful if you want the same data structure to be encoded as
 the same JSON text (given the same overall settings). If it is disabled,
 the same hash might be encoded differently even if contains the same data,
 as key-value pairs have no inherent ordering in Perl.
 calls).
 JSON::XS will only attempt to parse the JSON text once it is sure it
 has enough text to get a decisive result, using a very simple but
 truly incremental parser. This means that it sometimes won't stop as
-early as the full parser, for example, it doesn't detect parenthese
+early as the full parser, for example, it doesn't detect mismatched
-mismatches. The only thing it guarantees is that it starts decoding as
+parentheses. The only thing it guarantees is that it starts decoding as
 soon as a syntactically valid JSON text has been seen. This means you need
 to set resource limits (e.g. C<max_size>) to ensure the parser will stop
 parsing in the presence if syntax errors.
 The following methods implement this incremental parser.
 Numbers containing a fractional or exponential part will always be
 represented as numeric (floating point) values, possibly at a loss of
 precision (in which case you might lose perfect roundtripping ability, but
 the JSON number will still be re-encoded as a JSON number).
+Note that precision is not accuracy - binary floating point values cannot
+represent most decimal fractions exactly, and when converting from and to
+floating point, JSON::XS only guarantees precision up to but not including
+the leats significant bit.
 =item true, false
 These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>,
 respectively. They are overloaded to act almost exactly like the numbers
 C<1> and C<0>. You can check whether a scalar is a JSON boolean by using
 You can not currently force the type in other, less obscure, ways. Tell me
 if you need this capability (but don't forget to explain why it's needed
 :).
+Note that numerical precision has the same meaning as under Perl (so
+binary to decimal conversion follows the same rules as in Perl, which
+can differ to other languages). Also, your perl interpreter might expose
+extensions to the floating point numbers of your platform, such as
+infinities or NaN's - these cannot be represented in JSON, and it is an
+error to pass those in.
 =back
 =head1 ENCODING/CODESET FLAG NOTES
 well - using C<eval> naively simply I<will> cause problems.
 Another problem is that some javascript implementations reserve
 some property names for their own purposes (which probably makes
 them non-ECMAscript-compliant). For example, Iceweasel reserves the
-C<__proto__> property name for it's own purposes.
+C<__proto__> property name for its own purposes.
 If that is a problem, you could parse try to filter the resulting JSON
 output for these property strings, e.g.:
    $json =~ s/"__proto__"\s*:/"__proto__renamed":/g;
 that difficult or long) and finally make YAML compatible to it, and
 educating users about the changes, instead of spreading lies about the
 real compatibility for many I<years> and trying to silence people who
 point out that it isn't true.
-Addendum/2009: the YAML 1.2 spec is still incomaptible with JSON, even
+Addendum/2009: the YAML 1.2 spec is still incompatible with JSON, even
-though the incompatibilities have been documented (and are known to
+though the incompatibilities have been documented (and are known to Brian)
-Brian) for many years and the spec makes explicit claims that YAML is a
+for many years and the spec makes explicit claims that YAML is a superset
-superset of JSON. It would be so easy to fix, but apparently, bullying and
+of JSON. It would be so easy to fix, but apparently, bullying people and
 corrupting userdata is so much easier.
 =back
 process simulations - use fork, it's I<much> faster, cheaper, better).
 (It might actually work, but you have been warned).
+=head1 THE PERILS OF SETLOCALE
+Sometimes people avoid the Perl locale support and directly call the
+system's setlocale function with C<LC_ALL>.
+This breaks both perl and modules such as JSON::XS, as stringification of
+numbers no longer works correcly (e.g. C<$x = 0.1; print "$x"+1> might
+print C<1>, and JSON::XS might output illegal JSON as JSON::XS relies on
+perl to stringify numbers).
+The solution is simple: don't call C<setlocale>, or use it for only those
+categories you need, such as C<LC_MESSAGES> or C<LC_CTYPE>.
+If you need C<LC_NUMERIC>, you should enable it only around the code that
+actually needs it (avoiding stringification of numbers), and restore it
+afterwards.
 =head1 BUGS
 While the goal of this module is to be correct, that unfortunately does
 not mean it's bug-free, only that I think its design is bug-free. If you
 keep reporting bugs they will be fixed swiftly, though.

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Comparing JSON-XS/XS.pm (file contents): Revision 1.130 by root, Thu Mar 11 17:36:09 2010 UTC vs. Revision 1.139 by root, Thu May 23 09:31:32 2013 UTC

Diff Legend

Comparing JSON-XS/XS.pm (file contents):
Revision 1.130 by root, Thu Mar 11 17:36:09 2010 UTC vs.
Revision 1.139 by root, Thu May 23 09:31:32 2013 UTC