NAME
    PICA::Data - PICA record processing

SYNOPSIS
        use PICA::Data ':all';
        $parser = pica_parser( xml => @options );
        $writer = pica_writer( plain => @options );
   
        use PICA::Parser::XML;
        use PICA::Writer::Plain;
        $parser = PICA::Parser::XML->new( @options );
        $writer = PICA::Writer::Plain->new( @options );

        while ( my $record = $parser->next ) {
        
            # function accessors
            my $ppn      = pica_value($record, '003@0');
            my $holdings = pica_holdings($record);
            my $items    = pica_items($record);
            ...

            # object accessors (if parser option 'bless' enabled)
            my $ppn      = $record->{_id};
            my $ppn      = $record->value('003@0');
            my $holdings = $record->holdings;
            my $items    = $record->items;
            ...

        }
  
        # parse single record from string
        my $record = pica_parser('plain', \"...")->next;

DESCRIPTION
    PICA::Data provides methods, classes, and functions to process PICA+
    records in Perl.

    PICA+ is the internal data format of the Local Library System (LBS) and
    the Central Library System (CBS) of OCLC, formerly PICA. Similar library
    formats are the MAchine Readable Cataloging format (MARC) and the
    Maschinelles Austauschformat fuer Bibliotheken (MAB). In addition to
    PICA+ in CBS there is the cataloging format Pica3 which can losslessly
    be convert to PICA+ and vice versa.

    Records in PICA::Data are encoded either as as array of arrays, the
    inner arrays representing PICA fields, or as an object with two fields,
    "_id" and "record", the latter holding the record as array of arrays,
    and the former holding the record identifier, stored in field "003@",
    subfield 0. For instance a minimal record with just one field "003@":

        {
          _id    => '12345X',
          record => [
            [ '003@', undef, '0' => '12345X' ]
          ]
        }

    or in short form:

        [ [ '003@', undef, '0' => '12345X' ] ]

    PICA path expressions (see PICA::Path) can be used to facilitate
    processing PICA+ records.

FUNCTIONS
    The following functions can be exported on request (use export tag
    ":all" to get all of them):

  pica_parser( $type [, @options] )
    Create a PICA parsers object. Case of the type is ignored and additional
    parameters are passed to the parser's constructor:

    *   PICA::Parser::XML for type "xml" or "picaxml" (PICA-XML)

    *   PICA::Parser::Plus for type "plus" or "picaplus" (normalized PICA+)

    *   PICA::Parser::Plain for type "plain" or "picaplain" (human-readable
        PICA+)

  pica_writer( $type [, @options] )
    Create a PICA writer object in the same way as "pica_parser" with one of

    *   PICA::Writer::XML for type "xml" or "picaxml" (PICA-XML)

    *   PICA::Writer::Plus for type "plus" or "picaplus" (normalized PICA+)

    *   PICA::Writer::Plain for type "plain" or "picaplain" (human-readable
        PICA+)

  pica_path( $path )
    Equivalent to <PICA::Path-new($path)|PICA::Path>>.

  pica_values( $record, $path )
  pica_value( $record, $path )
  pica_fields( $record, $path )
  pica_holdings( $record )
  pica_head2s( $record )
  pica_xml_struct( $xml, %options )
    Convert PICA-XML, expressed in XML::Struct structure into an (optionally
    blessed) PICA record structure.

ACCESSORS
    All accessors of "PICA::Data" are also available as "FUNCTIONS",
    prefixed with "pica_" (see "SYNOPSIS").

  values( $path )
    Extract a list of subfield values from a PICA record based on a PICA
    path expression.

  value( $path )
    Same as "values" but only returns the first value.

  fields( $path )
    Returns a PICA record limited to fields specified in a PICA path
    expression. Always returns an array reference.

  holdings
    Returns a list (as array reference) of local holding records (level 1
    and 2), where the "_id" of each record contains the ILN (subfield
    "101@a").

  items
    Returns a list (as array reference) of item records (level 1), where the
    "_id" of each record contains the EPN (subfield "203@/**0").

CONTRIBUTORS
    Johann Rolschewski, "<rolschewski@gmail.com>"

    Jakob Voss "<voss@gbv.de>"

COPYRIGHT AND LICENSE
    Copyright 2014- Johann Rolschewski and Jakob Voss

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

SEE ALSO
    *   PICA::Record (deprecated) implemented an alternative framework for
        processing PICA+ records.

    *   Use Catmandu::PICA for processing PICA records with the Catmandu
        toolkit, for instance to convert PICA XML to plain PICA+:

           catmandu convert PICA --type xml to PICA --type plain < picadata.xml

