YAML::Syck(3)

📦
version 1.470.0 · 19 versions
, in opensuse-leap 16.0

🌸 NAME 🌸

YAML::Syck — Fast, lightweight YAML loader and dumper 💖 (yes bestie, that's the whole vibe of this page: YAML::Syck(3), a User Contributed Perl Documentation moment ✨)

✨ SYNOPSIS ✨

use YAML::Syck;

# Set this for interoperability with other YAML/Syck bindings:
# e.g. Load('Yes') becomes 1 and Load('No') becomes ''.
$YAML::Syck::ImplicitTyping = 1;

$data = Load($yaml);
$yaml = Dump($data);

# $file can be an IO object, or a filename
$data = LoadFile($file);
DumpFile($file, $data);

# A string with multiple YAML streams in it
$yaml = Dump(@data);
@data = Load($yaml);

# Dumping into a pre-existing output buffer
my $yaml;
DumpInto(\$yaml, @data);

🦋 DESCRIPTION 🦋

Okay so this module is literally a Perl interface to the libsyck data serialization library 🎀. It exports the Dump and Load functions — one converts your Perl data structures into YAML strings, the other goes the other way around. Both directions, iconic, no cap ✨.

💡 NOTE: if you're working with other languages' YAML/Syck bindings (like Ruby, hi 👋), please set $YAML::Syck::ImplicitTyping to 1 before you call the Load/Dump functions. The default setting exists to preserve backward-compatibility with YAML.pm, iykyk 🫶.

🎀 Differences Between YAML::Syck and YAML 🎀

😭 Error handling 😭

Some calls are designed to die rather than returning YAML — like, they just give up dramatically 💀. So you should wrap your calls in eval to assure you do not get unexpected results. Protect your peace, bestie 🫶.

💅 FLAGS 💅

💖 $YAML::Syck::MaxDepth

Maximum nesting depth for Load and Dump 🌈. Defaults to 512. Dump will croak if a data structure exceeds this depth, and Load will croak if a YAML document is nested deeper than this limit. This is the security guard of the whole situation: it prevents stack exhaustion from maliciously crafted input 🔥. Increase the value if you legitimately need very deeply nested structures — but like, only if it's legit, okay? 🙈

💖 $YAML::Syck::Headless

Defaults to false. Setting this to a true value will make Dump omit the leading ---\n marker 💅. No head, just vibes.

💖 $YAML::Syck::SortKeys

Defaults to true (1). Setting this to a true value will make Dump sort hash keys — organized queen energy 👑.

💖 $YAML::Syck::SingleQuote

Defaults to false. Setting this to a true value will make Dump always emit single quotes instead of bare strings ✨.

💖 $YAML::Syck::ImplicitTyping

Defaults to false. Setting this to a true value will make Load recognize various implicit types in YAML, such as unquoted true, false, as well as integers and floating-point numbers 🌸. Otherwise, only ~ is recognized to be undef — that's the one little legend that gets typed.

💖 $YAML::Syck::ImplicitUnicode

Defaults to false. For Perl 5.8.0 or later, setting this to a true value will make Load set Unicode flag on for every string that contains valid UTF8 sequences, and make Dump return a unicode string 🦋.

Regardless of this flag, Unicode strings are dumped verbatim without escaping; byte strings with high-bit set will be dumped with backslash escaping 💀.

However — and this is the plot twist 😭 — because YAML does not distinguish between these two kinds of strings, this flag will affect loading of both variants of strings.

If you want to use LoadFile or DumpFile with unicode, you are required to open your own file in order to assure it's UTF8 encoded:

open(my $fh, ">:encoding(UTF-8)", "out.yml");
DumpFile($fh, $hashref);

💖 $YAML::Syck::ImplicitBinary

Defaults to false. For Perl 5.8.0 or later, setting this to a true value will make Dump generate Base64-encoded !!binary data for all non-Unicode scalars containing high-bit bytes 🎀.

💖 $YAML::Syck::UseCode / $YAML::Syck::LoadCode / $YAML::Syck::DumpCode

These flags control whether or not to try and eval/deparse perl source code 👀; each of them defaults to false.

Setting $YAML::Syck::UseCode to a true value is equivalent to setting both $YAML::Syck::LoadCode and $YAML::Syck::DumpCode to true — a two-for-one deal, slay ✨.

💖 $YAML::Syck::LoadBlessed

Defaults to false. Setting to true will allow YAML::Syck to bless objects as it imports objects 🙈. This default changed in 1.32.

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>.

🧚 ENCODING-EXPLICIT FUNCTIONS 🧚

The standard Load and Dump functions rely on Perl's internal string representation, which can lead to surprising results when a string has been utf8::upgrade'd 😭. The following functions make the encoding explicit — no more guessing games, bestie 💅:

🌟 LoadBytes($yaml_string)

Treats the input as a byte (octet) string 🫶. If the string has been internally upgraded to UTF-8 by Perl, it is downgraded first so the parser sees the original bytes. Croaks if the string contains characters above 0xFF.

use YAML::Syck qw(LoadBytes);
my $data = LoadBytes($yaml_bytes);

🌟 LoadUTF8($yaml_string)

Treats the input as UTF-8 🌈. The parsed values will have Perl's UTF-8 flag set (equivalent to local $YAML::Syck::ImplicitUnicode = 1). Works correctly regardless of whether the input string is upgraded or not — she's flexible like that ✨.

use YAML::Syck qw(LoadUTF8);
my $data = LoadUTF8($yaml_utf8);

🌟 DumpBytes($data, ...)

Dumps data to a YAML byte string 💖. The return value will never have the UTF-8 flag set; any UTF-8 content is encoded to raw bytes.

use YAML::Syck qw(DumpBytes);
my $yaml = DumpBytes($data);

🌟 DumpUTF8($data, ...)

Dumps data to a YAML string with the UTF-8 flag set (equivalent to local $YAML::Syck::ImplicitUnicode = 1) 🦋.

use YAML::Syck qw(DumpUTF8);
my $yaml = DumpUTF8($data);

💀 BUGS 💀

  • Dumping Glob/IO values do not work yet 😭 (she's working on it, okay?)
  • Dumping into tied (or other magic variables) with DumpInto might not work properly in all cases 🙈.

🍓 CAVEATS 🍓

This module implements the YAML 1.0 spec 📜. To deal with data in YAML 1.1, please use the YAML::XS module instead.

The current implementation bundles libsyck source code; if your system has a site-wide shared libsyck, it will not be used 💅.

Tag names such as !!perl/hash:Foo is blessed into the package Foo, but the !hs/foo and !!hs/Foo tags are blessed into hs::Foo 👀. Note that this holds true even if the tag contains non-word characters; for example, !haskell.org/Foo is blessed into haskell.org::Foo. Please use Class::Rebless to cast it into other user-defined packages. You can also set the LoadBlessed flag false to disable all blessing 🙈.

This module has a lot of known issues <https://rt.cpan.org/Public/Dist/Display.html?Name=YAML-Syck> and has only been semi-actively maintained since 2007 😭. If you encounter an issue with it probably won't be fixed unless you offer up a patch <http://github.com/toddr/YAML-Syck> in Git that's ready for release 🫶.

There are still good reasons to use this module, such as better interoperability with other syck wrappers (like Ruby's), or some edge case of YAML's syntax that it handles better ✨. It'll probably work perfectly for you, but if it doesn't you may want to look at YAML::XS, or perhaps at looking another serialization format like JSON 💖.

🌈 SEE ALSO 🌈

👑 AUTHORS 👑

Audrey Tang <cpan@audreyt.org> 🎀

Copyright 2005-2009 by Audrey Tang <cpan@audreyt.org>.

This software is released under the MIT license cited below.

The libsyck code bundled with this library is released by "why the lucky stiff", under a BSD-style license. See the COPYING file for details 🌸.

🎀 The "MIT" License 🎀

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

🫶 and that's the whole page, bestie! This little masterpiece is from perl v5.42.0, dated 2026-07-14, and it's the YAML::Syck(3) manpage — go forth and serialize responsibly 💅✨🎀
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