YAML::PP(3) User Contributed Perl Documentation YAML::PP(3)
NAME
YAML::PP - YAML 1.2 processor
SYNOPSIS
WARNING: Most of the inner API is not stable yet.
Here are a few examples of the basic load and dump methods:
use YAML::PP;
my $ypp = YAML::PP->new;
my $yaml = <<'EOM';
--- # Document one is a mapping
name: Tina
age: 29
favourite language: Perl
--- # Document two is a sequence
- plain string
- 'in single quotes'
- "in double quotes we have escapes! like \t and \n"
- | # a literal block scalar
line1
line2
- > # a folded block scalar
this is all one
single line because the
linebreaks will be folded
EOM
my @documents = $ypp->load_string($yaml);
my @documents = $ypp->load_file($filename);
my $yaml = $ypp->dump_string($data1, $data2);
$ypp->dump_file($filename, $data1, $data2);
# Enable perl data types and objects
my $ypp = YAML::PP->new(schema => [qw/ + Perl /]);
my $yaml = $yp->dump_string($data_with_perl_objects);
# Legacy interface
use YAML::PP qw/ Load Dump LoadFile DumpFile /;
my @documents = Load($yaml);
my @documents = LoadFile($filename);
my @documents = LoadFile($filehandle);
my $yaml = = Dump(@documents);
DumpFile($filename, @documents);
DumpFile($filenhandle @documents);
Some utility scripts, mostly useful for debugging:
# Load YAML into a data structure and dump with Data::Dumper
yamlpp-load < file.yaml
# Load and Dump
yamlpp-load-dump < file.yaml
# Print the events from the parser in yaml-test-suite format
yamlpp-events < file.yaml
# Parse and emit events directly without loading
yamlpp-parse-emit < file.yaml
# Create ANSI colored YAML. Can also be useful for invalid YAML, showing
# you the exact location of the error
yamlpp-highlight < file.yaml
DESCRIPTION
YAML::PP is a modular YAML processor.
It aims to support "YAML 1.2" and "YAML 1.1". See .
Some (rare) syntax elements are not yet supported and documented below.
YAML is a serialization language. The YAML input is called "YAML
Stream". A stream consists of one or more "Documents", separated by a
line with a document start marker "---". A document optionally ends
with the document end marker "...".
This allows one to process continuous streams additionally to a fixed
input file or string.
The YAML::PP frontend will currently load all documents, and return
only the first if called with scalar context.
The YAML backend is implemented in a modular way that allows one to add
custom handling of YAML tags, perl objects and data types. The inner
API is not yet stable. Suggestions welcome.
You can check out all current parse and load results from the yaml-
test-suite here:
METHODS
new
my $ypp = YAML::PP->new;
# use YAML 1.2 Failsafe Schema
my $ypp = YAML::PP->new( schema => ['Failsafe'] );
# use YAML 1.2 JSON Schema
my $ypp = YAML::PP->new( schema => ['JSON'] );
# use YAML 1.2 Core Schema
my $ypp = YAML::PP->new( schema => ['Core'] );
# Die when detecting cyclic references
my $ypp = YAML::PP->new( cyclic_refs => 'fatal' );
my $ypp = YAML::PP->new(
boolean => 'perl',
schema => ['Core'],
cyclic_refs => 'fatal',
indent => 4,
header => 1,
footer => 0,
version_directive => 0,
);
Options:
boolean
Values: "perl" (currently default), "JSON::PP", "boolean",
"perl_experimental"
This option is for loading and dumping.
In case of perl 5.36 and later, builtin booleans should work out of
the box (since YAML::PP >= 0.38.0).
print YAML::PP->new->dump_string([ builtin::true, !1 ]);
# ---
# - true
# - false
For earlier perl versions, you can use "pseudo" booleans like
documented in the following examples.
# load/dump booleans via boolean.pm
my $ypp = YAML::PP->new( boolean => 'boolean' );
# load/dump booleans via JSON::PP::true/false
my $ypp = YAML::PP->new( boolean => 'JSON::PP' );
You can also specify more than one class, comma separated. This is
important for dumping.
boolean => 'JSON::PP,boolean'
Booleans will be loaded as JSON::PP::Booleans, but when dumping, also
'boolean' objects will be recognized
boolean => 'JSON::PP,*'
Booleans will be loaded as JSON::PP::Booleans, but when dumping, all
currently supported boolean classes will be recognized
boolean => '*'
Booleans will be loaded as perl booleans, but when dumping, all
currently supported boolean classes will be recognized
boolean => ''
Booleans will be loaded as perl booleans, but when dumping, nothing
will be recognized as booleans.
This option is for backwards compatibility for perl versions < 5.36,
if you rely on [!!1, !1] being dumped as [1, ''].
The option "perl_experimental" was introduced when experimental
boolean support was added to perl 5.36. Since it will not be
experimental anymore in perl 5.40 \o/ the option is deprecated and
the same as "perl".
schema
Default: "['Core']"
This option is for loading and dumping.
Array reference. Here you can define what schema to use. Supported
standard Schemas are: "Failsafe", "JSON", "Core", "YAML1_1".
To get an overview how the different Schemas behave, see
Additionally you can add further schemas, for example "Merge".
cyclic_refs
Default: "fatal" (since 0.037)
Before the default was "allow", but this can lead to memory leaks
when loading on untrusted data, so it was changed to "fatal" by
default.
This option is for loading only.
Defines what to do when a cyclic reference is detected when
loading.
# fatal - die
# warn - Just warn about them and replace with undef
# ignore - replace with undef
# allow - Default
duplicate_keys
Default: 0
Since version 0.027
This option is for loading.
The YAML Spec says duplicate mapping keys should be forbidden.
When set to true, duplicate keys in mappings are allowed (and will
overwrite the previous key).
When set to false, duplicate keys will result in an error when
loading.
This is especially useful when you have a longer mapping and don't
see the duplicate key in your editor:
---
a: 1
b: 2
# .............
a: 23 # error
indent
Default: 2
This option is for dumping.
Use that many spaces for indenting
width
Since version 0.025
Default: 80
This option is for dumping.
Maximum columns when dumping.
This is only respected when dumping flow collections right now.
in the future it will be used also for wrapping long strings.
header
Default: 1
This option is for dumping.
Print document header "---"
footer
Default: 0
This option is for dumping.
Print document footer "..."
yaml_version
Since version 0.020
This option is for loading and dumping.
Default: 1.2
Note that in this case, a directive "%YAML 1.1" will basically be
ignored and everything loaded with the "1.2 Core" Schema.
If you want to support both YAML 1.1 and 1.2, you have to specify
that, and the schema ("Core" or "YAML1_1") will be chosen
automatically.
my $yp = YAML::PP->new(
yaml_version => ['1.2', '1.1'],
);
This is the same as
my $yp = YAML::PP->new(
schema => ['+'],
yaml_version => ['1.2', '1.1'],
);
because the "+" stands for the default schema per version.
When loading, and there is no %YAML directive, 1.2 will be
considered as default, and the "Core" schema will be used.
If there is a "%YAML 1.1" directive, the "YAML1_1" schema will be
used.
Of course, you can also make 1.1 the default:
my $yp = YAML::PP->new(
yaml_version => ['1.1', '1.2'],
);
You can also specify 1.1 only:
my $yp = YAML::PP->new(
yaml_version => ['1.1'],
);
In this case also documents with "%YAML 1.2" will be loaded with
the "YAML1_1" schema.
version_directive
Since version 0.020
This option is for dumping.
Default: 0
Print Version Directive "%YAML 1.2" (or "%YAML 1.1") on top of each
YAML document. It will use the first version specified in the
"yaml_version" option.
preserve
Since version 0.021
Default: false
This option is for loading and dumping.
Preserving scalar styles is still experimental.
use YAML::PP::Common qw/ :PRESERVE /;
# Preserve the order of hash keys
my $yp = YAML::PP->new( preserve => PRESERVE_ORDER );
# Preserve the quoting style of scalars
my $yp = YAML::PP->new( preserve => PRESERVE_SCALAR_STYLE );
# Preserve block/flow style (since 0.024)
my $yp = YAML::PP->new( preserve => PRESERVE_FLOW_STYLE );
# Preserve alias names (since 0.027)
my $yp = YAML::PP->new( preserve => PRESERVE_ALIAS );
# Combine, e.g. preserve order and scalar style
my $yp = YAML::PP->new( preserve => PRESERVE_ORDER | PRESERVE_SCALAR_STYLE );
Do NOT rely on the internal implementation of it.
If you load the following input:
---
z: 1
a: 2
---
- plain
- 'single'
- "double"
- |
literal
- >
folded
---
block mapping: &alias
flow sequence: [a, b]
same mapping: *alias
flow mapping: {a: b}
with this code:
my $yp = YAML::PP->new(
preserve => PRESERVE_ORDER | PRESERVE_SCALAR_STYLE
| PRESERVE_FLOW_STYLE | PRESERVE_ALIAS
);
my ($hash, $styles, $flow) = $yp->load_file($file);
$yp->dump_file($hash, $styles, $flow);
Then dumping it will return the same output.
Note that YAML allows repeated definition of anchors. They cannot
be preserved with YAML::PP right now. Example:
---
- &seq [a]
- *seq
- &seq [b]
- *seq
Because the data could be shuffled before dumping again, the anchor
definition could be broken. In this case repeated anchor names will
be discarded when loading and dumped with numeric anchors like
usual.
Implementation:
When loading, hashes will be tied to an internal class
("YAML::PP::Preserve::Hash") that keeps the key order.
Scalars will be returned as objects of an internal class
("YAML::PP::Preserve::Scalar") with overloading. If you assign to
such a scalar, the object will be replaced by a simple scalar.
# assignment, style gets lost
$styles->[1] .= ' append';
You can also pass 1 as a value. In this case all preserving options
will be enabled, also if there are new options added in the future.
There are also methods to create preserved nodes from scratch. See
the preserved_(scalar|mapping|sequence) "METHODS" below.
load_string
my $doc = $ypp->load_string("foo: bar");
my @docs = $ypp->load_string("foo: bar\n---\n- a");
Input should be Unicode characters.
So if you read from a file, you should decode it, for example with
Encode::decode().
Note that in scalar context, "load_string" and "load_file" return the
first document (like YAML::Syck), while YAML and YAML::XS return the
last.
load_file
my $doc = $ypp->load_file("file.yaml");
my @docs = $ypp->load_file("file.yaml");
Strings will be loaded as unicode characters.
dump_string
my $yaml = $ypp->dump_string($doc);
my $yaml = $ypp->dump_string($doc1, $doc2);
my $yaml = $ypp->dump_string(@docs);
Input strings should be Unicode characters.
Output will return Unicode characters.
So if you want to write that to a file (or pass to YAML::XS, for
example), you typically encode it via Encode::encode().
dump_file
$ypp->dump_file("file.yaml", $doc);
$ypp->dump_file("file.yaml", $doc1, $doc2);
$ypp->dump_file("file.yaml", @docs);
Input data should be Unicode characters.
dump
This will dump to a predefined writer. By default it will just use the
YAML::PP::Writer and output a string.
my $writer = MyWriter->new(\my $output);
my $yp = YAML::PP->new(
writer => $writer,
);
$yp->dump($data);
preserved_scalar
Since version 0.024
Experimental. Please report bugs or let me know this is useful and
works.
You can define a certain scalar style when dumping data. Figuring out
the best style is a hard task and practically impossible to get it
right for all cases. It's also a matter of taste.
use YAML::PP::Common qw/ PRESERVE_SCALAR_STYLE YAML_LITERAL_SCALAR_STYLE /;
my $yp = YAML::PP->new(
preserve => PRESERVE_SCALAR_STYLE,
);
# a single linebreak would normally be dumped with double quotes: "\n"
my $scalar = $yp->preserved_scalar("\n", style => YAML_LITERAL_SCALAR_STYLE );
my $data = { literal => $scalar };
my $dump = $yp->dump_string($data);
# output
---
literal: |+
...
preserved_mapping, preserved_sequence
Since version 0.024
Experimental. Please report bugs or let me know this is useful and
works.
With this you can define which nodes are dumped with the more compact
flow style instead of block style.
If you add "PRESERVE_ORDER" to the "preserve" option, it will also keep
the order of the keys in a hash.
use YAML::PP::Common qw/
PRESERVE_ORDER PRESERVE_FLOW_STYLE
YAML_FLOW_MAPPING_STYLE YAML_FLOW_SEQUENCE_STYLE
/;
my $yp = YAML::PP->new(
preserve => PRESERVE_FLOW_STYLE | PRESERVE_ORDER
);
my $hash = $yp->preserved_mapping({}, style => YAML_FLOW_MAPPING_STYLE);
# Add values after initialization to preserve order
%$hash = (z => 1, a => 2, y => 3, b => 4);
my $array = $yp->preserved_sequence([23, 24], style => YAML_FLOW_SEQUENCE_STYLE);
my $data = $yp->preserved_mapping({});
%$data = ( map => $hash, seq => $array );
my $dump = $yp->dump_string($data);
# output
---
map: {z: 1, a: 2, y: 3, b: 4}
seq: [23, 24]
loader
Returns or sets the loader object, by default YAML::PP::Loader
dumper
Returns or sets the dumper object, by default YAML::PP::Dumper
schema
Returns or sets the schema object
default_schema
Creates and returns the default schema
FUNCTIONS
The functions "Load", "LoadFile", "Dump" and "DumpFile" are provided as
a drop-in replacement for other existing YAML processors. No function
is exported by default.
Note that in scalar context, "Load" and "LoadFile" return the first
document (like YAML::Syck), while YAML and YAML::XS return the last.
Load
use YAML::PP qw/ Load /;
my $doc = Load($yaml);
my @docs = Load($yaml);
Works like "load_string".
LoadFile
use YAML::PP qw/ LoadFile /;
my $doc = LoadFile($file);
my @docs = LoadFile($file);
my @docs = LoadFile($filehandle);
Works like "load_file".
Dump
use YAML::PP qw/ Dump /;
my $yaml = Dump($doc);
my $yaml = Dump(@docs);
Works like "dump_string".
DumpFile
use YAML::PP qw/ DumpFile /;
DumpFile($file, $doc);
DumpFile($file, @docs);
DumpFile($filehandle, @docs);
Works like "dump_file".
PLUGINS
You can alter the behaviour of YAML::PP by using the following schema
classes:
YAML::PP::Schema::Failsafe
One of the three YAML 1.2 official schemas
YAML::PP::Schema::JSON
One of the three YAML 1.2 official schemas.
YAML::PP::Schema::Core
One of the three YAML 1.2 official schemas. Default
YAML::PP::Schema::YAML1_1
Schema implementing the most common YAML 1.1 types
YAML::PP::Schema::Perl
Serializing Perl objects and types
YAML::PP::Schema::Binary
Serializing binary data
YAML::PP::Schema::Tie::IxHash
Deprecated. See option "preserve"
YAML::PP::Schema::Merge
YAML 1.1 merge keys for mappings
YAML::PP::Schema::Include
Include other YAML files via "!include" tags
To make the parsing process faster, you can plugin the libyaml parser
with YAML::PP::LibYAML.
IMPLEMENTATION
The process of loading and dumping is split into the following steps:
Load:
YAML Stream Tokens Event List Data Structure
---------> ---------> --------->
lex parse construct
Dump:
Data Structure Event List YAML Stream
---------> --------->
represent emit
You can dump basic perl types like hashes, arrays, scalars (strings,
numbers). For dumping blessed objects and things like coderefs have a
look at YAML::PP::Perl/YAML::PP::Schema::Perl.
YAML::PP::Lexer
The Lexer is reading the YAML stream into tokens. This makes it
possible to generate syntax highlighted YAML output.
Note that the API to retrieve the tokens will change.
YAML::PP::Parser
The Parser retrieves the tokens from the Lexer. The main YAML
content is then parsed with the Grammar.
YAML::PP::Grammar
YAML::PP::Constructor
The Constructor creates a data structure from the Parser events.
YAML::PP::Loader
The Loader combines the constructor and parser.
YAML::PP::Dumper
The Dumper will delegate to the Representer
YAML::PP::Representer
The Representer will create Emitter events from the given data
structure.
YAML::PP::Emitter
The Emitter creates a YAML stream.
YAML::PP::Parser
Still TODO:
Implicit collection keys
---
[ a, b, c ]: value
Implicit mapping in flow style sequences
This is supported since 0.029 (except some not relevant cases):
---
[ a, b, c: d ]
# equals
[ a, b, { c: d } ]
Plain mapping keys ending with colons
---
key ends with two colons::: value
This was implemented in 0.037.
Supported Characters
If you have valid YAML that's not parsed, or the other way round,
please create an issue.
Line and Column Numbers
You will see line and column numbers in the error message. The
column numbers might still be wrong in some cases.
Error Messages
The error messages need to be improved.
Unicode Surrogate Pairs
Currently loaded as single characters without validating
Possibly more
YAML::PP::Constructor
The Constructor now supports all three YAML 1.2 Schemas, Failsafe, JSON
and Core. Additionally you can choose the schema for YAML 1.1 as
"YAML1_1".
Too see what strings are resolved as booleans, numbers, null etc. look
at .
You can choose the Schema like this:
my $ypp = YAML::PP->new(schema => ['JSON']); # default is 'Core'
The Tags "!!seq" and "!!map" are still ignored for now.
It supports:
Handling of Anchors/Aliases
Like in modules like YAML, the Constructor will use references for
mappings and sequences, but obviously not for scalars.
YAML::XS uses real aliases, which allows also aliasing scalars. I
might add an option for that since aliasing is now available in
pure perl.
Boolean Handling
You can choose between 'perl' (1/'', currently default), 'JSON::PP'
and 'boolean'.pm for handling boolean types. That allows you to
dump the data structure with one of the JSON modules without losing
information about booleans.
Numbers
Numbers are created as real numbers instead of strings, so that
they are dumped correctly by modules like JSON::PP or JSON::XS, for
example.
Complex Keys
Mapping Keys in YAML can be more than just scalars. Of course, you
can't load that into a native perl structure. The Constructor will
stringify those keys with Data::Dumper instead of just returning
something like HASH(0x55dc1b5d0178).
Example:
use YAML::PP;
use JSON::PP;
my $ypp = YAML::PP->new;
my $coder = JSON::PP->new->ascii->pretty->allow_nonref->canonical;
my $yaml = <<'EOM';
complex:
?
?
a: 1
c: 2
: 23
: 42
EOM
my $data = $yppl->load_string($yaml);
say $coder->encode($data);
__END__
{
"complex" : {
"{'{a => 1,c => 2}' => 23}" : 42
}
}
TODO:
Parse Tree
I would like to generate a complete parse tree, that allows you to
manipulate the data structure and also dump it, including all
whitespaces and comments. The spec says that this is throwaway
content, but I read that many people wish to be able to keep the
comments.
YAML::PP::Dumper, YAML::PP::Emitter
The Dumper should be able to dump strings correctly, adding quotes
whenever a plain scalar would look like a special string, like "true",
or when it contains or starts with characters that are not allowed.
Most strings will be dumped as plain scalars without quotes. If they
contain special characters or have a special meaning, they will be
dumped with single quotes. If they contain control characters,
including <"\n">, they will be dumped with double quotes.
It will recognize JSON::PP::Boolean and boolean.pm objects and dump
them correctly.
Numbers which also have a "PV" flag will be recognized as numbers and
not as strings:
my $int = 23;
say "int: $int"; # $int will now also have a PV flag
That means that if you accidentally use a string in numeric context, it
will also be recognized as a number:
my $string = "23";
my $something = $string + 0;
print $yp->dump_string($string);
# will be emitted as an integer without quotes!
The layout is like libyaml output:
key:
- a
- b
- c
---
- key1: 1
key2: 2
key3: 3
---
- - a1
- a2
- - b1
- b2
FAQ - Frequently Asked Questions
Are "<<" merge keys supported?
Yes, this can be enabled optionally, see YAML::PP::Schema::Merge
Is there a linter / formatter for YAML
There is the widely used "yamllint"
, based on python's PyYAML. It is
very configurable and will report errors or warnings. It cannot
format.
Now there is also YAML::Tidy, which will format the given file
according to your configuration. So far only a few configuration
options exist, but they can already be quite helpful.
Which YAML module should I use?
There are many YAML modules on CPAN. For historical reasons some of
them aren't handling YAML correctly.
Most of them are not compatible with the YAML spec and with each other,
meaning they can interpret the same YAML differently.
The behaviours we are discussing here can be divided into parsing
issues (syntax) and loading/constructing issues (for example type
resolving which decides what is a number, boolean or null).
See also (parsing) and
(loading).
"YAML.pm"
It was written even before the YAML 1.0 spec was finished and by
that enabled perl users to process YAML very early. It might work
for you if you have simple data, but it's missing quite some
features and can also produce YAML that doesn't roundtrip. Nowadays
it might be a good idea to switch.
YAML::XS
A libyaml binding that is robust and widely used. However, there
are two things to consider.
1. (syntax) libyaml diverged from the spec in several aspects. They
are rare though. 2. The type resolving does not adhere to YAML 1.1
or YAML 1.2, meaning it is
incompatible with other YAML libraries in perl or other
languages.
YAML::Tiny
It implements both a tiny subset of YAML, but also a superset.
Meaning it will happily accept some YAML documents that are not
officially valid. Type resolving is also not implemented according
to the spec.
YAML::Syck
A binding to libsyck. It is even less compatible to YAML than
libyaml. Also type resolving is not implemented according to the
spec.
YAML::PP
Regarding YAML syntax, it is the second most YAML 1.2 compatible
perl module. The cases it cannot (yet) parse are not relevant in
perl programming, e.g. hash keys that are not strings. Regarding
type resolving, it is compatible with the YAML 1.2 Core schema, so
it should be possible to exchange data as YAML with other libraries
in other languages. One downside is that it is the slowest perl
YAML module.
YAML::Parser
This is a parser generated by the YAML grammar, and it's passing
all official tests. A YAML::PP::Ref frontend exists that you can
use just like YAML::PP. It is quite slow (although it might be ok
for small files depending on the use case). The error messages it
creates on invalid YAML are not helpful currently.
YAML::PP::LibYAML
This combines the YAML::LibYAML::API binding for parsing with the
YAML::PP frontend for loading and type resolving. It is faster
than YAML::PP but slower than YAML::XS. The divergence from the
YAML spec regarding syntax is usually not a problem, and at the
same time you have the advantage of being compatible to the YAML
1.2 Core Schema.
WHY
Why did I start to write a new YAML module?
All the available parsers and loaders for Perl are behaving
differently, and more important, aren't conforming to the spec.
YAML::XS is doing pretty well, but "libyaml" only handles YAML 1.1 and
diverges a bit from the spec. The pure perl loaders lack support for a
number of features.
I was going over YAML.pm issues end of 2016, integrating old patches
from rt.cpan.org and creating some pull requests myself. I realized
that it would be difficult to patch YAML.pm to parse YAML 1.1 or even
1.2, and it would also break existing usages relying on the current
behaviour.
In 2016 Ingy dot Net initiated two really cool projects:
"YAML TEST SUITE"
"YAML EDITOR"
These projects are a big help for any developer. So I got the idea to
write my own parser and started on New Year's Day 2017. Without the
test suite and the editor I would have never started this.
I also started another YAML Test project which allows one to get a
quick overview of which frameworks support which YAML features:
"YAML TEST MATRIX"
YAML TEST SUITE
It contains almost 400 test cases and expected parsing events and more.
There will be more tests coming. This test suite allows you to write
parsers without turning the examples from the Specification into tests
yourself. Also the examples aren't completely covering all cases - the
test suite aims to do that.
Thanks also to Felix Krause, who is writing a YAML parser in Nim. He
turned all the spec examples into test cases.
YAML EDITOR
This is a tool to play around with several YAML parsers and loaders in
vim.
The project contains the code to build the frameworks (16 as of this
writing) and put it into one big Docker image.
It also contains the yaml-editor itself, which will start a vim in the
docker container. It uses a lot of funky vimscript that makes playing
with it easy and useful. You can choose which frameworks you want to
test and see the output in a grid of vim windows.
Especially when writing a parser it is extremely helpful to have all
the test cases and be able to play around with your own examples to see
how they are handled.
YAML TEST MATRIX
I was curious to see how the different frameworks handle the test
cases, so, using the test suite and the docker image, I wrote some code
that runs the tests, manipulates the output to compare it with the
expected output, and created a matrix view.
You can find the latest build at
CONTRIBUTORS
Ingy dot Net
Ingy is one of the creators of YAML. In 2016 he started the YAML
Test Suite and the YAML Editor. He also made useful suggestions on
the class hierarchy of YAML::PP.
Felix "flyx" Krause
Felix answered countless questions about the YAML Specification.
SEE ALSO
YAML
YAML::XS
YAML::Syck
YAML::Tiny
YAML::PP::LibYAML
YAML::LibYAML::API
YAML::Tidy
SPONSORS
The Perl Foundation sponsored this
project (and the YAML Test Suite) with a grant of 2500 USD in
2017-2018.
COPYRIGHT AND LICENSE
Copyright 2017-2022 by Tina Muller
This library is free software and may be distributed under the same
terms as perl itself.
perl v5.38.2 2024-02-14 YAML::PP(3)