NAME

       MARC::Spec::Field - field specification

SYNOPSIS

           use MARC::Spec::Field;

           my $field = MARC::Spec::Field->new('246');
           say ref $field;           # MARC::Spec::Field
           say $field->tag;          # 246
           say $field->index_start;  # 0
           say $field->index_end;    # '#'

DESCRIPTION

       MARC::Spec::Field is the field specification of a MARC::Spec.

       See MARCspec - A common MARC record path language <http://marcspec.github.io/MARCspec/>
       for further details on the syntax.

METHODS

       Some methods are inherited from MARC::Spec::Structure.

   new(Str)
       Create a new MARC::Spec::Field instance. Parameter must be a valid MARCspec field tag.

   add_subspec(MARC::Spec::Subspec)
       Appends a subspec to the array of the attribute subspecs. Parameter must be an instance of
       MARC::Spec::Subspec.

   add_subspecs(ArrayRef[MARC::Spec::Subspec])
       Appends subspecs to the array of the attribute subspecs. Parameter must be an ArrayRef and
       elements must be instances of MARC::Spec::Subspec.

   to_string
       Returns the spec as a string.

PREDICATES

       Some predicates are inherited from MARC::Spec::Structure.

   has_char_start
       True if attribute char_start has an value and false otherwise.

   has_char_end
       True if attribute char_end has an value and false otherwise.

   has_char_pos
       True if attribute char_pos has an value and false otherwise.

   has_subspecs
       Returns true if attribute subspecs has an value and false otherwise.

ATTRIBUTES

       Some attributes are inherited from MARC::Spec::Structure.

   base
       Obligatory. Scalar. The base Field spec without subspecs.

   tag
       Obligatory. The field tag.

   char_pos
       If defined, the character position or range. Only present if
       MARC::Spec::Field::$char_start is defined.

   char_start
       If defined, the beginning character position of a character position or range.

   char_end
       If defined, the ending character position of a character position or range.  Only present
       if MARC::Spec::Field::$char_start is defined.

   char_length
       The difference of MARC::Spec::Field::$char_start and MARC::Spec::Field::$char_end if both
       are numeric (or else -1).  Only present if MARC::Spec::Field::$char_start is defined.

   char_pos
       If defined, the character position or range.  Only present if
       MARC::Spec::Field::$char_start is defined.

   index_start
       Obligatory. The beginning index of field repetitions. Maybe a positiv integer or the
       character '#'.  Default is 0.

   index_end
       Obligatory. The ending index of field repetitions. Maybe a positiv integer or the
       character '#'.  Default is '#'.

   index_length
       Obligatory. The difference of MARC::Spec::Field::$index_start and
       MARC::Spec::Field::$index_end if both are numeric.  Default is -1.

   subspecs
       Optional. An array of instances of MARC::Spec::Subspec, thus all subspecs in this array
       MUST be validated as a combination with the boolean 'AND', and/or an array of arrays (AoA)
       of instances of MARC::Spec::Subspec, thus all subspecs in this AoA must be validated as a
       combination with the boolean 'OR'.

       See MARC::Spec::Subspec for description of attributes of MARC::Spec::Subspec.

AUTHOR

       Carsten Klee "<klee at cpan.org>"

CONTRIBUTORS

       •   Johann Rolschewski, "<jorol at cpan>"

COPYRIGHT AND LICENSE

       This software is copyright (c) 2016 by Carsten Klee.

       This is free software; you can redistribute it and/or modify it under the same terms as
       the Perl 5 programming language system itself.

BUGS

       Please report any bugs to <https://github.com/MARCspec/MARC-Spec/issues>

SEE ALSO

       •   MARC::Spec

       •   MARC::Spec::Subfield

       •   MARC::Spec::Indicator

       •   MARC::Spec::Subspec

       •   MARC::Spec::Structure

       •   MARC::Spec::Comparisonstring

       •   MARC::Spec::Parser