NAME

       YAML::XS - Perl YAML Serialization using XS and libyaml

SYNOPSIS

           use YAML::XS;

           my $yaml = Dump [ 1..4 ];
           my $array = Load $yaml;

DESCRIPTION

       Kirill Simonov's "libyaml" is arguably the best YAML implementation. The C library is
       written precisely to the YAML 1.1 specification. It was originally bound to Python and was
       later bound to Ruby.

       This module is a Perl XS binding to libyaml which offers Perl the best YAML support to
       date.

       This module exports the functions "Dump", "Load", "DumpFile" and "LoadFile". These
       functions are intended to work exactly like "YAML.pm"'s corresponding functions. Only
       "Load" and "Dump" are exported by default.

CONFIGURATION

       •   $YAML::XS::LoadBlessed (since v0.69)

           Default: false.

           The default was changed in version 0.81.

           When set to false, it will not bless data into objects, which can be a security
           problem, when loading YAML from an untrusted source. It will silently ignore the tag
           and just load the data unblessed.

           In PyYAML, this is called SafeLoad.

           If set to true, it will load the following YAML as objects:

               ---
               local: !Foo::Bar [a]
               perl: !!perl/hash:Foo::Bar { a: 1 }
               regex: !!perl/regexp:Foo::Bar pattern

           You can create any kind of object with YAML. The creation itself is not the critical
           part. If the class has a "DESTROY" method, it will be called once the object is
           deleted. An example with File::Temp removing files can be found at
           <https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=862373>.

       •   $YAML::XS::ForbidDuplicateKeys (since 0.84)

           Default: false

           When set to true, "Load" will die when encountering a duplicate key in a hash, e.g.

               key: value
               key: another value

           This can be useful for bigger YAML documents where it is not that obvious, and it is
           recommended to set it to true. That's also what a YAML loader should do by default
           according to the YAML specification.

       •   $YAML::XS::UseCode

       •   $YAML::XS::DumpCode

       •   $YAML::XS::LoadCode

           If enabled supports deparsing and evaling of code blocks.

           Note that support for loading code was added in version 0.75, although $LoadCode was
           documented already in earlier versions.

       •   $YAML::XS::QuoteNumericStrings

           When true (the default) strings that look like numbers but have not been numified will
           be quoted when dumping.

           This ensures leading that things like leading zeros and other formatting are
           preserved.

       •   $YAML::XS::Boolean (since v0.67)

           Default is undef.

           When set to "JSON::PP" or "boolean", the plain (unquoted) strings "true" and "false"
           will be loaded as "JSON::PP::Boolean" or "boolean.pm" objects. Those objects will be
           dumped again as plain "true" or "false".

           It will try to load [JSON::PP] or [boolean] and die if it can't be loaded.

           With that it's possible to add new "real" booleans to a data structure:

               local $YAML::XS::Boolean = "JSON::PP"; # or "boolean"
               my $data = Load("booltrue: true");
               $data->{boolfalse} = JSON::PP::false;
               my $yaml = Dump($data);
               # boolfalse: false
               # booltrue: true

           It also lets booleans survive when loading YAML via YAML::XS and encode it in JSON via
           one of the various JSON encoders, which mostly support JSON::PP booleans.

           Please note that JSON::PP::Boolean and boolean.pm behave a bit differently. Ideally
           you should only use them in boolean context.

           If not set, booleans are loaded as special perl variables "PL_sv_yes" and "PL_sv_no",
           which have the disadvantage that they are readonly, and you can't add those to an
           existing data structure with pure perl.

           If you simply need to load "perl booleans" that are true or false in boolean context,
           you will be fine with the default setting.

       •   $YAML::XS::Indent (since v0.76)

           Default is 2.

           Sets the number of spaces for indentation for "Dump".

USING YAML::XS WITH UNICODE

       Handling unicode properly in Perl can be a pain. YAML::XS only deals with streams of utf8
       octets. Just remember this:

           $perl = Load($utf8_octets);
           $utf8_octets = Dump($perl);

       There are many, many places where things can go wrong with unicode. If you are having
       problems, use Devel::Peek on all the possible data points.

LIBYAML

       You can find out (since v.079) which libyaml version this module was built with:

           my $libyaml_version = YAML::XS::LibYAML::libyaml_version();

SEE ALSO

       •   YAML.pm

       •   YAML::Syck

       •   YAML::Tiny

       •   YAML::PP

       •   YAML::PP::LibYAML

AUTHOR

       Ingy döt Net ingy@ingy.net <mailto:ingy@ingy.net>

COPYRIGHT AND LICENSE

       Copyright 2007-2023 - Ingy döt Net

       This program is free software; you can redistribute it and/or modify it under the same
       terms as Perl itself.

       See <http://www.perl.com/perl/misc/Artistic.html>