NAME
    Tiny::YAML - YAML::Tiny Done Right

PREAMBLE
    Don't even look at this yet. It's a super early release and will be
    bootstrapping for a while.

    This module uses a real grammar to parse/load YAML.

    Stay tuned...

    TODO - Funny rant about the shortcomings of YAML::Tiny

SYNOPSIS
    Assuming "file.yaml" like this:

        ---
        rootproperty: blah
        section:
          one: two
          three: four
          Foo: Bar
          empty: ~

    Read and write "file.yaml" like this:

        use Tiny::YAML;

        # Open the config
        my $data = Tiny::YAML::LoadFile( 'file.yaml' );

        # Get a reference to the first document
        my $config = $data->[0];

        # Or read properties directly
        my $root = $data->[0]->{rootproperty};
        my $one  = $data->[0]->{section}->{one};
        my $Foo  = $data->[0]->{section}->{Foo};

        # Change data directly
        $data->[0]->{newsection} = { this => 'that' }; # Add a section
        $data->[0]->{section}->{Foo} = 'Not Bar!';     # Change a value
        delete $data->[0]->{section};                  # Delete a value

        # Save the document back to the file
        Tiny::YAML::DumpFile( 'file.yaml' );

    To create a new YAML file from scratch:

        # Create a new object with a single hashref document
        my $data = Dump( { wibble => "wobble" } );

        # Add an arrayref document
        push @$data, [ 'foo', 'bar', 'baz' ];

        # Save both documents to a file
        $data->( 'data.yaml' );

    Then "data.yaml" will contain:

        ---
        wibble: wobble
        ---
        - foo
        - bar
        - baz

DESCRIPTION
    "Tiny::YAML" is a perl class for reading and writing YAML-style files,
    written with as little code as possible, reducing load time and memory
    overhead.

    Most of the time it is accepted that Perl applications use a lot of
    memory and modules. The "Tiny::" family of modules is specifically
    intended to provide an ultralight and zero-dependency alternative to
    many more-thorough standard modules.

    This module is primarily for reading human-written files (like simple
    config files) and generating very simple human-readable files. Note that
    I said *human- readable* and not *geek-readable*. The sort of files that
    your average manager or secretary should be able to look at and make
    sense of.

    Tiny::YAML does not generate comments, it won't necessarily preserve the
    order of your hashes, and it will normalise if reading in and writing
    out again.

    It only supports a very basic subset of the full YAML specification.

    Usage is targeted at files like Perl's META.yaml, for which a small and
    easily- embeddable module is extremely attractive.

    Features will only be added if they are human readable, and can be
    written in a few lines of code. Please don't be offended if your request
    is refused. Someone has to draw the line, and for Tiny::YAML that
    someone is me.

    If you need something with more power move up to YAML (7 megabytes of
    memory overhead) or YAML::XS (6 megabytes memory overhead and requires a
    C compiler).

    To restate, Tiny::YAML does *not* preserve your comments, whitespace, or
    the order of your YAML data. But it should round-trip from Perl
    structure to file and back again just fine.

FUNCTIONS
    Tiny::YAML implements a number of functions to add compatibility with
    the YAML API. These should be a drop-in replacement.

    "Dump"
            my $string = Dump(list-of-Perl-data-structures);

        Turn Perl data into YAML. This function works very much like
        Data::Dumper::Dumper().

        It takes a list of Perl data structures and dumps them into a
        serialized form.

        It returns a character string containing the YAML stream. Be sure to
        encode it as UTF-8 before serializing to a file or socket.

        The structures can be references or plain scalars.

        Dies on any error.

    "Load"
            my @data_structures = Load(string-containing-a-YAML-stream);

        Turn YAML into Perl data. This is the opposite of Dump.

        Just like Storable's thaw() function or the eval() function in
        relation to Data::Dumper.

        It parses a character string containing a valid YAML stream into a
        list of Perl data structures representing the individual YAML
        documents. Be sure to decode the character string correctly if the
        string came from a file or socket.

            my $last_data_structure = Load(string-containing-a-YAML-stream);

        For consistency with YAML.pm, when Load is called in scalar context,
        it returns the data structure corresponding to the last of the YAML
        documents found in the input stream.

        Dies on any error.

    "DumpFile(filepath, list)"
        Writes the YAML stream to a file with UTF-8 encoding instead of just
        returning a string.

        Dies on any error.

    "LoadFile(filepath)"
        Reads the YAML stream from a UTF-8 encoded file instead of a string.

        Dies on any error.

TINY YAML SPECIFICATION
    This section of the documentation provides a specification for "Tiny
    YAML", a subset of the YAML specification.

    It is based on and described comparatively to the YAML 1.1 Working Draft
    2004-12- 28 specification, located at
    <http://yaml.org/spec/current.html>.

    Terminology and chapter numbers are based on that specification.

  1. Introduction and Goals
    The purpose of the Tiny YAML specification is to describe a useful
    subset of the YAML specification that can be used for typical
    document-oriented use cases such as configuration files and simple data
    structure dumps.

    Many specification elements that add flexibility or extensibility are
    intentionally removed, as is support for complex data structures, class
    and object-orientation.

    In general, the Tiny YAML language targets only those data structures
    available in JSON, with the additional limitation that only simple keys
    are supported.

    As a result, all possible Tiny YAML documents should be able to be
    transformed into an equivalent JSON document, although the reverse is
    not necessarily true (but will be true in simple cases).

    As a result of these simplifications the Tiny YAML specification should
    be implementable in a (relatively) small amount of code in any language
    that supports Perl Compatible Regular Expressions (PCRE).

  2. Introduction
    Tiny YAML supports three data structures. These are scalars (in a
    variety of forms), block-form sequences and block-form mappings.
    Flow-style sequences and mappings are not supported, with some minor
    exceptions detailed later.

    The use of three dashes "---" to indicate the start of a new document is
    supported, and multiple documents per file/stream is allowed.

    Both line and inline comments are supported.

    Scalars are supported via the plain style, single quote and double
    quote, as well as literal-style and folded-style multi-line scalars.

    The use of explicit tags is not supported.

    The use of "null" type scalars is supported via the ~ character.

    The use of *bool* type scalars is not supported.

    However, serializer implementations should take care to explicitly
    escape strings that match a *bool* keyword in the following set to
    prevent other implementations that do support *bool* accidentally
    reading a string as a boolean

        true|false|null

    The use of anchors and aliases is not supported.

    The use of directives is supported only for the %YAML directive.

  3. Processing Tiny YAML Information
    Processes
        The YAML specification dictates three-phase serialization and
        three-phase deserialization.

        The Tiny YAML specification does not mandate any particular
        methodology or mechanism for parsing.

        Any compliant parser is only required to parse a single document at
        a time. The ability to support streaming documents is optional and
        most likely non-typical.

        Because anchors and aliases are not supported, the resulting
        representation graph is thus directed but (unlike the main YAML
        specification) *acyclic*.

        Circular references/pointers are not possible, and any Tiny YAML
        serializer detecting a circular reference should error with an
        appropriate message.

    Presentation Stream
        Tiny YAML reads and write UTF-8 encoded files. Operations on strings
        expect or produce Unicode characters not UTF-8 encoded bytes.

    Loading Failure Points
        Tiny YAML parsers and emitters are not expected to recover from, or
        adapt to, errors. The specific error modality of any implementation
        is not dictated (return codes, exceptions, etc.) but is expected to
        be consistent.

  4. Syntax
    Character Set
        Tiny YAML streams are processed in memory as Unicode characters and
        read/written with UTF-8 encoding.

        The escaping and unescaping of the 8-bit YAML escapes is required.

        The escaping and unescaping of 16-bit and 32-bit YAML escapes is not
        required.

    Indicator Characters
        Support for the "~" null/undefined indicator is required.

        Implementations may represent this as appropriate for the underlying
        language.

        Support for the "-" block sequence indicator is required.

        Support for the "?" mapping key indicator is *not* required.

        Support for the ":" mapping value indicator is required.

        Support for the "," flow collection indicator is *not* required.

        Support for the "[" flow sequence indicator is *not* required, with
        one exception (detailed below).

        Support for the "]" flow sequence indicator is *not* required, with
        one exception (detailed below).

        Support for the "{" flow mapping indicator is *not* required, with
        one exception (detailed below).

        Support for the "}" flow mapping indicator is *not* required, with
        one exception (detailed below).

        Support for the "#" comment indicator is required.

        Support for the "&" anchor indicator is *not* required.

        Support for the "*" alias indicator is *not* required.

        Support for the "!" tag indicator is *not* required.

        Support for the "|" literal block indicator is required.

        Support for the ">" folded block indicator is required.

        Support for the "'" single quote indicator is required.

        Support for the """ double quote indicator is required.

        Support for the "%" directive indicator is required, but only for
        the special case of a %YAML version directive before the "---"
        document header, or on the same line as the document header.

    For example:

        %YAML 1.1
        ---
        - A sequence with a single element

    Special Exception:

    To provide the ability to support empty sequences and mappings, support
    for the constructs [] (empty sequence) and {} (empty mapping) are
    required.

    For example,

        %YAML 1.1
        # A document consisting of only an empty mapping
        --- {}
        # A document consisting of only an empty sequence
        --- []
        # A document consisting of an empty mapping within a sequence
        - foo
        - {}
        - bar

    Syntax Primitives

    Other than the empty sequence and mapping cases described above, Tiny
    YAML supports only the indentation-based block-style group of contexts.

    All five scalar contexts are supported.

    Indentation spaces work as per the YAML specification in all cases.

    Comments work as per the YAML specification in all simple cases. Support
    for indented multi-line comments is *not* required.

    Separation spaces work as per the YAML specification in all cases.

    Tiny YAML Character Stream

    The only directive supported by the Tiny YAML specification is the %YAML
    language/version identifier. Although detected, this directive will have
    no control over the parsing itself.

    The parser must recognise both the YAML 1.0 and YAML 1.1+ formatting of
    this directive (as well as the commented form, although no explicit code
    should be needed to deal with this case, being a comment anyway)

    That is, all of the following should be supported.

        --- #YAML:1.0
        - foo

        %YAML:1.0
        ---
        - foo

        % YAML 1.1
        ---
        - foo

    Support for the %TAG directive is *not* required.

    Support for additional directives is *not* required.

    Support for the document boundary marker "---" is required.

    Support for the document boundary market "..." is *not* required.

    If necessary, a document boundary should simply by indicated with a
    "---" marker, with not preceding "..." marker.

    Support for empty streams (containing no documents) is required.

    Support for implicit document starts is required.

    That is, the following must be equivalent.

        # Full form
        %YAML 1.1
        ---
        foo: bar

        # Implicit form
        foo: bar

    Nodes

    Support for nodes optional anchor and tag properties is *not* required.

    Support for node anchors is *not* required.

    Support for node tags is *not* required.

    Support for alias nodes is *not* required.

    Support for flow nodes is *not* required.

    Support for block nodes is required.

    Scalar Styles

    Support for all five scalar styles is required as per the YAML
    specification, although support for quoted scalars spanning more than
    one line is *not* required.

    Support for multi-line scalar documents starting on the header is not
    required.

    Support for the chomping indicators on multi-line scalar styles is
    required.

    Collection Styles

    Support for block-style sequences is required.

    Support for flow-style sequences is *not* required.

    Support for block-style mappings is required.

    Support for flow-style mappings is *not* required.

    Both sequences and mappings should be able to be arbitrarily nested.

    Support for plain-style mapping keys is required.

    Support for quoted keys in mappings is *not* required.

    Support for "?"-indicated explicit keys is *not* required.

    Here endeth the specification.

  Additional Perl-Specific Notes
    For some Perl applications, it's important to know if you really have a
    number and not a string.

    That is, in some contexts is important that 3 the number is distinctive
    from 3 the string.

    Because even Perl itself is not trivially able to understand the
    difference (certainly without XS-based modules) Perl implementations of
    the Tiny YAML specification are not required to retain the
    distinctiveness of 3 vs 3.

SUPPORT
    Bugs should be reported via the CPAN bug tracker at
    "/github.com/ingydotnet/tiny-yaml- pm/issues" in http:

AUTHOR
    Ingy döt Net <ingy@cpan.org>

SEE ALSO
    YAML::Tiny
    YAML
    YAML::Syck
    Config::Tiny
    CSS::Tiny

COPYRIGHT
    Copyright 2014 Ingy döt Net

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

