YAML::XS - Perl YAML Serialization using XS and libyaml
use YAML::XS; my $yaml = Dump [ 1..4 ]; my $array = Load $yaml;
Kirill Siminov'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.
libyaml
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.
Dump
Load
DumpFile
LoadFile
YAML.pm
$YAML::XS::LoadBlessed
Default: true. The default might be changed to false in the future.
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
$YAML::XS::UseCode
$YAML::XS::DumpCode
$YAML::XS::LoadCode
If enabled supports deparsing and evaling of code blocks.
$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
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".
"JSON::PP"
"boolean"
true
false
JSON::PP::Boolean
boolean.pm
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 allows to let 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::Booolean 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.
PL_sv_yes
PL_sv_no
If you simply need to load "perl booleans" that are true or false in boolean context, you will be fine with the default setting.
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.
YAML::Syck
YAML::Tiny
Ingy döt Net <ingy@cpan.org>
Copyright 2007-2017. 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
To install YAML::LibYAML, copy and paste the appropriate command in to your terminal.
cpanm
cpanm YAML::LibYAML
CPAN shell
perl -MCPAN -e shell install YAML::LibYAML
For more information on module installation, please visit the detailed CPAN module installation guide.