JSON::Syck3pm

Usage

    use JSON::Syck; # no exports by default 
    my $data = JSON::Syck::Load($json);
    my $json = JSON::Syck::Dump($data);
    # $file can be an IO object, or a filename
    my $data = JSON::Syck::LoadFile($file);
    JSON::Syck::DumpFile($file, $data);
    # Dump into a pre-existing buffer
    my $json;
    JSON::Syck::DumpInto(\$json, $data);

Overview

JSON::Syck is a syck implementation of JSON parsing and generation. Because JSON is YAML (<http://redhanded.hobix.com/inspect/yamlIsJson.html>), using syck gives you a fast and memory-efficient parser and dumper for JSON data representation.

However, a newer module JSON::XS, has since emerged. It is more flexible, efficient and robust, so please consider using it instead of this module.

Difference with json

You might want to know the difference between the JSON module and this one.

Since JSON is a pure-perl module and JSON::Syck is based on libsyck, JSON::Syck is supposed to be very fast and memory efficient. See chansen's benchmark table at <http://idisk.mac.com/christian.hansen/Public/perl/serialize.pl>

JSON.pm comes with dozens of ways to do the same thing and lots of options, while JSON::Syck doesn't. There's only "Load" and "Dump".

Oh, and JSON::Syck doesn't use camelCase method names :-)

References

UTF-8 flags

By default this module doesn't touch any of utf-8 flags set in strings, and assumes UTF-8 bytes to be passed and emit.

However, when you set $JSON::Syck::ImplicitUnicode to 1, this module properly decodes UTF-8 binaries and sets UTF-8 flag everywhere, as in:

  JSON (UTF-8 bytes)   => Perl (UTF-8 flagged)
  JSON (UTF-8 flagged) => Perl (UTF-8 flagged)
  Perl (UTF-8 bytes)   => JSON (UTF-8 flagged)
  Perl (UTF-8 flagged) => JSON (UTF-8 flagged)

By default, JSON::Syck::Dump will only transverse up to 512 levels of a datastructure in order to avoid an infinite loop when it is presented with an circular reference.

However, you can set $JSON::Syck::MaxDepth to a larger value if you have very complex structures.

Unfortunately, there's no implicit way to dump Perl UTF-8 flagged data structure to utf-8 encoded JSON. To do this, simply use Encode module, e.g.:

  use Encode;
  use JSON::Syck qw(Dump);
  my $json = encode_utf8( Dump($data) );

Alternatively you can use Encode::JavaScript::UCS to encode Unicode strings as in %uXXXX form.

  use Encode;
  use Encode::JavaScript::UCS;
  use JSON::Syck qw(Dump);
  my $json_unicode_escaped = encode( 'JavaScript-UCS', Dump($data) );

Quoting

According to the JSON specification, all JSON strings are to be double-quoted. However, when embedding JavaScript in HTML attributes, it may be more convenient to use single quotes.

Set $JSON::Syck::SingleQuote to 1 will make both "Dump" and "Load" expect single-quoted string literals.