NAME
    Text::PO - Read and write PO files

SYNOPSIS
        use Text::PO;
        # Create a parser (include directives enabled by default)
        my $po = Text::PO->new;
        $po->debug(2);
        $po->parse( $poFile ) || die( $po->error );

        # Or disable include processing for this parsing
        $po->parse( $poFile, include => 0 );

        # Retrieve parsed elements
        my $hash = $po->as_hash;
        my $json = $po->as_json;

        # Serialize back to PO text
        my $str = $po->as_string;

        # Add data:
        my $e = $po->add_element(
            msgid  => 'Hello!',
            msgstr => 'Salut !',
        );
        my $e = $po->add_include(
            file  => 'include/me.po',
            after => 'Hello world!',
        );

        $po->remove_element( $e );

        # Iterate over elements
        $po->elements->foreach(sub
        {
            my $e = shift( @_ ); # $_ is also available
            if( $e->msgid_as_text eq 'Hello!' )
            {
                # do something
            }
        });

    Or, maybe using the object overloading directly:

        $po->elements->foreach(sub
        {
            my $e = shift( @_ ); # $_ is also available
            if( $e eq $other )
            {
                # do something
            }
        });

        # Write in a PO format to STDOUT
        $po->dump;
        # or to a file handle
        $po->dump( $io );

        # Synchronise data
        $po->sync( '/some/where/com.example.api.po' );
        $po->sync( $file_handle );

        # or merge
        $po->merge( '/some/where/com.example.api.po' );
        $po->merge( $file_handle );

VERSION
        v0.9.0

DESCRIPTION
    This module parse GNU PO (portable object) and POT (portable object
    template) files, making it possible to edit the localised text and write
    it back to a po file.

    Text::PO::MO reads and writes ".mo" (machine object) binary files.

    Thus, with those modules, you do not need to install "msgfmt", "msginit"
    of GNU. It is better if you have them though.

    Also, this distribution provides a way to export the "po" files in json
    format to be used from within JavaScript and a JavaScript class to load
    and use those files is also provided along with some command line
    scripts. See the "share" folder along with its own test units.

    Also, there is a script in "scripts" that can be used to transcode ".po"
    or "mo" files into json format and vice versa.

    For more information on the format of a PO element, check
    Text::PO::Element

CONSTRUCTOR
  new
    Create a new Text::PO object acting as an accessor.

    One object should be created per po file, because it stores internally
    the po data for that file in the Text::PO object instantiated.

    Returns the object.

    The following options can be provided:

    *   "domain"

        The PO domain.

    *   "header"

        An array reference of PO file header string. Those are often lines
        of comments preceded by a pound sign ("#"), possibly with some
        copyright information.

    *   "encoding"

        The content encoding of the file, such as "utf-8"

    *   "include"

        Defaults to true.

        A boolean value (1 or 0) to indicate whether the parser should
        recognise include directives or not.

    *   "max_recurse"

        Defaults to 32

        An unsigned integer value representing the maximum recursion allowed
        when "include" is enabled, and when the parser finds include
        directives.

    *   "meta"

        An hash reference of meta key-value pairs, with the keys in all
        lower case.

    *   "meta_keys"

        An array reference of meta keys found,

    *   "use_json"

        Defaults to true.

        A boolean value (1 or 0) to indicate whether to use JSON format.

  METHODS
  add_element
        my $elem = $po->add_element( $element_object,
            after => 'Some other text',
        );
        my $elem = $po->add_element(
            msgid   => 'Hello world!",
            msgstr  => 'Salut tout le monde !',
            comment => 'No comment',
            before  => 'Some other text',        # Add this new element before this msgid/include directive
        );

    This takes either of the following parameters, and adds the new element,
    if it does not already exist, to the list of elements:

    1. Text::PO::Element object + %options
        A Text::PO::Element object, possibly followed by an hash or hash
        reference of options.

    2. %options
        An hash or hash ref of options that will be passed to
        Text::PO::Element to create a new object.

    It returns the newly created element if it did not already exist, or the
    existing one found. Thus if you try to add an element data that already
    exists, this will prevent it and return the existing element object
    found.

    If an error occurred, it will set an error object and return "undef" in
    scalar context, or an empty list in list context.

    Supported options are:

    *   all the ones used in Text::PO::Element

    *   "before" / "after"

        A "msgid" or "include" directive value to add this element before or
        after.

  add_include
        my $elem = $po->add_include( $element_object,
            after => 'Some other text',
        );
        my $elem = $po->add_include(
            file    => 'include/me.po",
            comment => 'No comment',
            before  => 'Some other text',   # Add this new element before this msgid/include directive
        );

    This takes either of the following parameters, and adds the new include
    directive, if it does not already exist, to the list of elements:

    1. Text::PO::Element object + %options
        A Text::PO::Element object, possibly followed by an hash or hash
        reference of options.

    2. %options
        An hash or hash ref of options that will be passed to
        Text::PO::Element to create a new object.

    Note that the "file" parameter must be set in the element passed, or
    provided among the options used to create a new element.

    It returns the newly created element if it did not already exist, or the
    existing one found. Thus if you try to add an include directive that
    already exists, this will prevent it and return the existing element
    object found.

    If an error occurred, it will set an error object and return "undef" in
    scalar context, or an empty list in list context.

    Supported options are:

    *   all the ones used in Text::PO::Element

    *   "before" / "after"

        A "msgid" or "include" directive value to add this element before or
        after.

  added
    Returns an array object (Module::Generic::Array) of Text::PO::Element
    objects added during synchronisation.

  as_json
    This takes an optional hash reference of option parameters and return a
    json formatted string.

    All options take a boolean value. Possible options are:

    *   "indent"

        If true, JSON will indent the data.

        Default to false.

    *   "pretty"

        If true, this will return a human-readable json data.

    *   "sort"

        If true, this will instruct JSON to sort the keys. This makes it
        slower to generate.

        It defaults to false, which will use a pseudo random order set by
        perl.

    *   "utf8"

        If true, JSON will utf8 encode the data.

  as_hash
    Return the data parsed as an hash reference.

  as_string
    Serializes the current PO object into a single string containing valid
    GNU ".po" syntax. This is equivalent to calling "dump" into an in-memory
    scalar, but more convenient for tests or further processing.

        my $string = $po->as_string;

    This always returns a plain Perl string (not a blessed scalar or IO
    object) to avoid issues with string overloading.

  charset
    Sets or gets the character encoding for the po data. This will affect
    the "charset" parameter in "Content-Type" meta information.

  content_encoding
    Sets or gets the meta field value for "Content-Encoding"

  content_type
    Sets or gets the meta field value for "Content-Type"

  current_lang
    Returns the current language environment variable set, trying "LANGUAGE"
    and "LANG"

  decode
    Given a string, this will decode it using the character set specified
    with "encoding"

  domain
    Sets or gets the domain (or namespace) for this PO. Something like
    "com.example.api"

  dump
    Given an optional filehandle, or STDOUT by default, it will print to
    that filehandle in a format suitable to the po file.

    Thus, one could create a perl script, read a po file, then redirect the
    output of the dump back to another po file like

        ./po_script.pl en_GB.po > new_en_GB.po

    It returns the Text::PO object used.

  elements
    Returns the array reference of all the Text::PO::Element objects

  encoding
    Sets or gets the character set encoding for the GNU PO file. Typically
    this should be "utf-8"

  exists
    Given a Text::PO::Element object, it will check if this object exists in
    its current stack. To achieve this, it will check if both the "msgid"
    and the "msgstr" exists and match. If you only want to check if the
    "msgid" exists, use the "msgid_only" option as explained below.

    It takes an optional hash or hash reference of options as follows:

    *   "msgid_only"

        Boolean. If true, this will check only if the "msgid" already
        exists, and not the corresponding "msgstr"

    It returns true of false accordingly.

  hash
    Returns the data of the po file as an hash reference with each key
    representing a string and its value the localised version.

  header
    Access the headers data for this po file. The data is an array
    reference.

  include
        $po->include(1);   # enable include directives
        $po->include(0);   # disable include directives
        my $bool = $po->include;

    Controls whether "$include "file.po"" directives are recognised during
    parsing.

    Include support is enabled by default.

    Include directives may appear in comments, using one of the following
    forms:

        # $include "other.po"
        #. $include 'relative/path.po'
        #   $include "shared/common.po"

    When include processing is enabled, any referenced file is parsed
    recursively. Only valid PO entries
    ("msgid"/"msgstr"/"msgid_plural"/"msgctxt" blocks and special comments)
    from included files are merged into the caller’s namespace; header
    blocks and meta sections of include files are ignored.

    This feature allows modular PO files, shared error message bundles, and
    structured localisation domains without a separate preprocessing step.

  language
    Sets or gets the meta field value for "Language"

  language_team
    Sets or gets the meta field value for "Language-Team"

  last_translator
    Sets or gets the meta field value for "Last-Translator"

  max_recurse
        $po->max_recurse(20);
        my $limit = $po->max_recurse;

    Sets or gets the maximum recursion depth allowed when processing include
    directives.

    The default is 32.

    If the recursion limit is exceeded (for example because of accidental
    self-inclusion or a circular include chain), parsing will abort and
    "error" will contain a descriptive message including the file path and
    line number where recursion overflow occurred.

    This protects users from infinite loops and malicious PO input.

  merge
    This takes the same parameters as "sync" and will merge the current data
    with the target data and return the newly created Text::PO object

  meta
    This sets or return the given meta information. The meta field name
    provided is case insensitive and you can replace dashes ("-") with
    underscore (<_>)

        $po->meta( 'Project-Id-Version' => 'MyProject 1.0' );
        # or this will also work
        $po->meta( project_id_version => 'MyProject 1.0' );

    It can take a hash ref, a hash, or a single element. If a single element
    is provided, it return its corresponding value.

    This returns its internal hash of meta information.

  meta_keys
    This is an hash reference of meta information.

  mime_version
    Sets or gets the meta field value for "MIME-Version"

  new_element
    Provided with an hash or hash reference of property-value pairs, and
    this will pass those information to Text::PO::Element and return the new
    object.

  normalise_meta
    Given a meta field, this will return a normalised version of it, ie a
    field name with the right case and dash instead of underscore
    characters.

  parse
        $po->parse( $filepath );
        $po->parse( $filepath, include => 0 );
        $po->parse( $fh, max_recurse => 20 );

    Parses a GNU ".po" file or a filehandle and loads its entries into the
    current object. Returns the current Text::PO instance on success. Upon
    error, it sets an error object and returns "undef" in scalar context,
    and an empty list in list context.

   Include processing
    If include processing is enabled (see "include"), the parser recognises
    the following non-standard directives:

        # $include "path.po"
        #.$include "relative.po"

    Relative paths are resolved against the directory of the parent file.

    When an include directive is seen:

    1.  A new Text::PO object is created for the included file.

    2.  The effective "include" and "max_recurse" settings are passed to the
        child parser.

    3.  Only PO elements ("msgid"/"msgstr"/"msgctl"/"msgid_plural" entries,
        and special comments) from the included file are merged into the
        parent’s "elements" list. Header metadata from included files is
        ignored.

    4.  Circular references are detected. A descriptive error is attached to
        the directive line and parsing continues for the parent file.

    5.  If the included file has some header meta information containing the
        header "Language" and if it does not match that of the parent, a
        warning is emitted if warnings are enabled.

   Options
    parse() accepts the following options:

    *   "include" (boolean)

        Override the parser’s include behaviour for this parse call.

    *   "max_recurse" (unsigned integer)

        Override the maximum include depth for this parse call.

  parse_date_to_object
    Provided with a date string and this returns a DateTime object

  parse_header_value
    Takes a header value such as "text/plain; charset="utf-8"" and this
    returns a "Text::PO::HeaderValue" object

  parse2hash
    Whether the pod file is stored as standard GNU po data or as json data,
    this method will read its data and return an hash reference of it.

  parse2object
    Takes a file path, parse the po file and loads its data onto the current
    object. It returns the current object.

  plural
    Sets or gets the plurality definition for this domain and locale used in
    the current object.

    If set, this will expect 2 parameters: 1) an integer representing the
    possible plurality for the given locale and 2) the expression that will
    be evaluated to assess which plural form to use.

    It returns an array reference representing those 2 values.

    If you want to find out the proper plural form for a given "locale", you
    should refer to the Unicode CLDR <https://cldr.unicode.org/> data, which
    can be accessed and queries via the module Locale::Unicode::Data:

        my $cldr = Locale::Unicode::Data->new;
        say $cldr->plural_forms( 'fr' ); # nplurals=2; plural=(n > 1);

  plural_forms
    Sets or gets the meta field value for "Plural-Forms"

  po_revision_date
    Sets or gets the meta field value for "PO-Revision-Date"

  pot_creation_date
    Sets or gets the meta field value for "POT-Creation-Date"

  project_id_version
    Sets or gets the meta field value for "Project-Id-Version"

  quote
    Given a string, it will escape carriage return, double quote and return
    it,

  remove_duplicates
    Takes a boolean value to enable or disable the removal of duplicates in
    the po file.

  remove_element
    Given a Text::PO::Element and this will remove it from the object
    elements list.

    If the value provided is not an Text::PO::Element object it will return
    an error.

    It returns a true value representing the number of elements removed or 0
    if none could be found.

  removed
    Sets or gets this boolean value.

  report_bugs_to
    Sets or gets the meta field value for "Report-Msgid-Bugs-To"

  quote
    Takes a string and escape the characters that needs to be and returns
    it.

  remove_duplicates
    Takes a boolean value and if true, this will remove duplicate msgid.

  removed
    Returns an array object (Module::Generic::Array) of Text::PO::Element
    removed during synchronisation.

  source
    Sets or gets an hash reference of parameters providing information about
    the source of the data.

    It could have an attribute "handle" with a glob as value or an attribute
    "file" with a filepath as value.

  sync
        $po->sync( '/some/where/com.example.api.po' );
        # or
        $po->sync({ file => '/some/where/com.example.api.po' });
        # or
        $po->sync({ handle => $file_handle });
        # or, if source of data has been set previously by parse()
        $po->parse( '/some/where/com.example.api.po' );
        # Do some change to the data, then:
        $po->sync;

    Given a file or a file handle, it will read the po file, and our current
    object will synchronise against it.

    It takes an hash or hash reference passed as argument, as optional
    parameters with the following properties:

    *   "file"

        File path

    *   "handle"

        Opened file handle

    This means that our object is the source and the file or filehandle
    representing the target po file is the recipient of the synchronisation.

    This method will return an error a file is provided, already exists, but
    is either a symbolic link or not a regular file ("-f" test), or a file
    handle is provided, but not currently opened.

    If a file path is provided, and the file does not yet exist, it will
    attempt to create it or return an error if it cannot. In this case, it
    will use "dump" to write all its data to file.

    If the target file was created, it will return the current object,
    otherwise it returns the newly created Text::PO representing the data
    synchronised.

  sync_fh
    Takes a file handle as its unique argument and synchronise the object
    data with the file handle. This means, the file handle provided must be
    opened in both read and write mode.

    What it does is that, after creating a new Text::PO object, it will
    first call "parse" on the file handle to load its data, and then add all
    of the current object data to the newly created object, and finally dump
    all back to the file handle using "dump"

    It will set two array of data: one for the elements that did not exist
    in the recipient data and thus were added and one for those elements in
    the target data that did not exist in the source object and thus were
    removed.

    If the option *append* is specified, however, it will not remove those
    elements in the target that doe not exist in the source one. You can get
    the same result by calling the method "merge" instead of "sync"

    You can get the data of each of those 2 arrays by calling the methods
    "added" and "removed" respectively.

    It returns the newly created Text::PO object containing the synchronised
    data.

  unquote
    Takes a string, unescape it and returns it.

  use_json
    Takes a boolean value and if true, this will save the data as json
    instead of regular po format.

    Saving data as json makes it quicker to load, but also enable the data
    to be used by JavaScript.

PRIVATE METHODS
  _can_write_fh
    Given a filehandle, returns true if it can be written to it or false
    otherwise.

  _set_get_meta_date
    Takes a meta field name for a date-type field and sets its value, if one
    is provided, or returns a DateTime object.

    If a value is provided, even a string, it will be converted to a
    DateTime object and a DateTime::Format::Strptime will be attached to it
    as a formatter so the stringification of the object produces a date
    compliant with PO format.

  _set_get_meta_value
    Takes a meta field name and sets or gets its value.

THREAD-SAFETY
    This module is thread-safe. All state is stored on a per-object basis,
    and the underlying file operations and data structures do not share
    mutable global state.

AUTHOR
    Jacques Deguest <jack@deguest.jp>

SEE ALSO
    Text::PO::Element, Text::PO::MO, Text::PO::Gettext

    <https://www.gnu.org/software/gettext/manual/html_node/PO-Files.html>,

    <https://en.wikipedia.org/wiki/Gettext>

    GNU documentation on header format
    <https://www.gnu.org/software/gettext/manual/html_node/Header-Entry.html
    >

COPYRIGHT & LICENSE
    Copyright (c) 2020-2025 DEGUEST Pte. Ltd.

    You can use, copy, modify and redistribute this package and associated
    files under the same terms as Perl itself.