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Mail::Field(3)                       User Contributed Perl Documentation                      Mail::Field(3)



NAME
       Mail::Field - Base class for manipulation of mail header fields

INHERITANCE
        Mail::Field is extended by
          Mail::Field::AddrList
          Mail::Field::Date
          Mail::Field::Generic

SYNOPSIS
        use Mail::Field;

        my $field = Mail::Field->new('Subject', 'some subject text');
        my $field = Mail::Field->new(Subject => 'some subject text');
        print $field->tag,": ",$field->stringify,"\n";

        my $field = Mail::Field->subject('some subject text');

DESCRIPTION
       "Mail::Field" creates and manipulates fields in MIME headers, collected within a Mail::Header object.
       Different field types have their own sub-class (extension), defining additional useful accessors to
       the field content.

       People are invited to merge their implementation to special fields into MailTools, to maintain a
       consistent set of packages and documentation.

METHODS
   Constructors
       Mail::Field (and it's sub-classes) define several methods which return new objects. These can all be
       categorized as constructor.

       Mail::Field->combine(FIELDS)
           Take a LIST of "Mail::Field" objects (which should all be of the same sub-class) and create a new
           object in that same class.

       Mail::Field->extract(TAG, HEAD [, INDEX ])
           Takes as arguments the tag name, a "Mail::Head" object and optionally an index.

           If the index argument is given then "extract" will retrieve the given tag from the "Mail::Head"
           object and create a new "Mail::Field" based object.  undef will be returned in the field does not
           exist.

           If the index argument is not given the the result depends on the context in which "extract" is
           called. If called in a scalar context the result will be as if "extract" was called with an index
           value of zero. If called in an array context then all tags will be retrieved and a list of
           "Mail::Field" objects will be returned.

       Mail::Field->new(TAG [, STRING | OPTIONS])
           Create an object in the class which defines the field specified by the TAG argument.

   "Fake" constructors
       $obj->create(OPTIONS)
           This constructor is used internally with preprocessed field information.  When called on an
           existing object, its original content will get replaced.

       $obj->parse()
           Parse a field line.

   Accessors
       $obj->set(OPTIONS)
           Change the settings (the content, but then smart) of this field.

       $obj->stringify()
           Returns the field as a string.

       $obj->tag()
       Mail::Field->tag()
           Return the tag (in the correct case) for this item.  Well, actually any casing is OK, because the
           field tags are treated case-insentitive; however people have some preferences.

   Smart accessors
       $obj->text([STRING])
           Without arguments, the field is returned as stringify() does.  Otherwise, the STRING is parsed
           with parse() to replace the object's content.

           It is more clear to call either stringify() or parse() directly, because this method does not add
           additional processing.

DETAILS
   SUB-CLASS PACKAGE NAMES
       All sub-classes should be called Mail::Field::name where name is derived from the tag using these
       rules.

       •   Consider a tag as being made up of elements separated by '-'

       •   Convert all characters to lowercase except the first in each element, which should be uppercase.

       •   name is then created from these elements by using the first N characters from each element.

       •   N is calculated by using the formula :-int((7 :int((7

               int((7 + #elements) / #elements)

       •   name is then limited to a maximum of 8 characters, keeping the first 8 characters.

       For an example of this take a look at the definition of the "_header_pkg_name()" subroutine in
       "Mail::Field"

DIAGNOSTICS
       Error: Undefined subroutine <method> called
           Mail::Field objects use autoloading to compile new functionality.  Apparently, the mehod called
           is not implemented for the specific class of the field object.

SEE ALSO
       This module is part of the MailTools distribution, http://perl.overmeer.net/mailtools/.

AUTHORS
       The MailTools bundle was developed by Graham Barr.  Later, Mark Overmeer took over maintenance
       without commitment to further development.

       Mail::Cap by Gisle Aas <aas@oslonett.no>.  Mail::Field::AddrList by Peter Orbaek <poe@cit.dk>.
       Mail::Mailer and Mail::Send by Tim Bunce <Tim.Bunce@ig.co.uk>.  For other contributors see ChangeLog.

LICENSE
       Copyrights 1995-2000 Graham Barr <gbarr@pobox.com> and 2001-2007 Mark Overmeer <perl@overmeer.net>.

       This program is free software; you can redistribute it and/or modify it under the same terms as Perl
       itself.  See http://www.perl.com/perl/misc/Artistic.html



perl v5.16.2                                     2012-08-29                                   Mail::Field(3)