1YAML::XS(3)           User Contributed Perl Documentation          YAML::XS(3)
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NAME

6       YAML::XS - Perl YAML Serialization using XS and libyaml
7

SYNOPSIS

9           use YAML::XS;
10
11           my $yaml = Dump [ 1..4 ];
12           my $array = Load $yaml;
13

DESCRIPTION

15       Kirill Simonov's "libyaml" is arguably the best YAML implementation.
16       The C library is written precisely to the YAML 1.1 specification. It
17       was originally bound to Python and was later bound to Ruby.
18
19       This module is a Perl XS binding to libyaml which offers Perl the best
20       YAML support to date.
21
22       This module exports the functions "Dump", "Load", "DumpFile" and
23       "LoadFile". These functions are intended to work exactly like
24       "YAML.pm"'s corresponding functions. Only "Load" and "Dump" are
25       exported by default.
26

CONFIGURATION

28       $YAML::XS::LoadBlessed (since v0.69)
29           Default: false.
30
31           The default was changed in version 0.81.
32
33           When set to false, it will not bless data into objects, which can
34           be a security problem, when loading YAML from an untrusted source.
35           It will silently ignore the tag and just load the data unblessed.
36
37           In PyYAML, this is called SafeLoad.
38
39           If set to true, it will load the following YAML as objects:
40
41               ---
42               local: !Foo::Bar [a]
43               perl: !!perl/hash:Foo::Bar { a: 1 }
44               regex: !!perl/regexp:Foo::Bar pattern
45
46           You can create any kind of object with YAML. The creation itself is
47           not the critical part. If the class has a "DESTROY" method, it will
48           be called once the object is deleted. An example with File::Temp
49           removing files can be found at
50           <https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=862373>
51
52       $YAML::XS::UseCode
53       $YAML::XS::DumpCode
54       $YAML::XS::LoadCode
55           If enabled supports deparsing and evaling of code blocks.
56
57           Note that support for loading code was added in version 0.75,
58           although $LoadCode was documented already in earlier versions.
59
60       $YAML::XS::QuoteNumericStrings
61           When true (the default) strings that look like numbers but have not
62           been numified will be quoted when dumping.
63
64           This ensures leading that things like leading zeros and other
65           formatting are preserved.
66
67       $YAML::XS::Boolean (since v0.67)
68           Default is undef.
69
70           When set to "JSON::PP" or "boolean", the plain (unquoted) strings
71           "true" and "false" will be loaded as "JSON::PP::Boolean" or
72           "boolean.pm" objects. Those objects will be dumped again as plain
73           "true" or "false".
74
75           It will try to load JSON::PP or boolean and die if it can't be
76           loaded.
77
78           With that it's possible to add new "real" booleans to a data
79           structure:
80
81                 local $YAML::XS::Boolean = "JSON::PP"; # or "boolean"
82                 my $data = Load("booltrue: true");
83                 $data->{boolfalse} = JSON::PP::false;
84                 my $yaml = Dump($data);
85                 # boolfalse: false
86                 # booltrue: true
87
88           It also lets booleans survive when loading YAML via YAML::XS and
89           encode it in JSON via one of the various JSON encoders, which
90           mostly support JSON::PP booleans.
91
92           Please note that JSON::PP::Boolean and boolean.pm behave a bit
93           differently.  Ideally you should only use them in boolean context.
94
95           If not set, booleans are loaded as special perl variables
96           "PL_sv_yes" and "PL_sv_no", which have the disadvantage that they
97           are readonly, and you can't add those to an existing data structure
98           with pure perl.
99
100           If you simply need to load "perl booleans" that are true or false
101           in boolean context, you will be fine with the default setting.
102
103       $YAML::XS::Indent (since v0.76)
104           Default is 2.
105
106           Sets the number of spaces for indentation for "Dump".
107

USING YAML::XS WITH UNICODE

109       Handling unicode properly in Perl can be a pain. YAML::XS only deals
110       with streams of utf8 octets. Just remember this:
111
112           $perl = Load($utf8_octets);
113           $utf8_octets = Dump($perl);
114
115       There are many, many places where things can go wrong with unicode. If
116       you are having problems, use Devel::Peek on all the possible data
117       points.
118

LIBYAML

120       You can find out (since v.079) which libyaml version this module was
121       built with:
122
123             my $libyaml_version = YAML::XS::LibYAML::libyaml_version();
124

SEE ALSO

126       •   YAML.pm
127
128       •   YAML::Syck
129
130       •   YAML::Tiny
131
132       •   YAML::PP
133
134       •   YAML::PP::LibYAML
135

AUTHOR

137       Ingy döt Net <ingy@cpan.org>
138

140       Copyright 2007-2020. Ingy döt Net.
141
142       This program is free software; you can redistribute it and/or modify it
143       under the same terms as Perl itself.
144
145       See <http://www.perl.com/perl/misc/Artistic.html>
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149perl v5.32.1                      2021-01-27                       YAML::XS(3)
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