/usr/share/perl5/Mail/Field.pod is in libmailtools-perl 2.18-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 | =encoding utf8
=head1 NAME
Mail::Field - Base class for manipulation of mail header fields
=head1 INHERITANCE
Mail::Field is extended by
Mail::Field::AddrList
Mail::Field::Date
Mail::Field::Generic
=head1 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');
=head1 DESCRIPTION
C<Mail::Field> creates and manipulates fields in MIME headers, collected
within a L<Mail::Header|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.
=head1 METHODS
=head2 Constructors
Mail::Field (and it's sub-classes) define several methods which return
new objects. These can all be categorized as constructor.
=over 4
=item Mail::Field-E<gt>B<combine>(FIELDS)
Take a LIST of C<Mail::Field> objects (which should all be of the same
sub-class) and create a new object in that same class.
=item Mail::Field-E<gt>B<extract>( TAG, HEAD [, INDEX ] )
Takes as arguments the tag name, a C<Mail::Head> object
and optionally an index.
If the index argument is given then C<extract> will retrieve the given tag
from the C<Mail::Head> object and create a new C<Mail::Field> based object.
I<undef> will be returned in the field does not exist.
If the index argument is not given the result depends on the context
in which C<extract> is called. If called in a scalar context the result
will be as if C<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
C<Mail::Field> objects will be returned.
=item Mail::Field-E<gt>B<new>( TAG [, STRING | OPTIONS] )
Create an object in the class which defines the field specified by
the TAG argument.
=back
=head2 "Fake" constructors
=over 4
=item $obj-E<gt>B<create>(OPTIONS)
This constructor is used internally with preprocessed field information.
When called on an existing object, its original content will get
replaced.
=item $obj-E<gt>B<parse>()
Parse a field line.
=back
=head2 Accessors
=over 4
=item $obj-E<gt>B<set>(OPTIONS)
Change the settings (the content, but then smart) of this field.
=item $obj-E<gt>B<stringify>()
Returns the field as a string.
=item $obj-E<gt>B<tag>()
=item Mail::Field-E<gt>B<tag>()
Return the tag (in the correct case) for this item. Well, actually any
casing is OK, because the field tags are treated case-insensitive; however
people have some preferences.
=back
=head2 Smart accessors
=over 4
=item $obj-E<gt>B<text>( [STRING] )
Without arguments, the field is returned as L<stringify()|Mail::Field/"Accessors"> does. Otherwise,
the STRING is parsed with L<parse()|Mail::Field/""Fake" constructors"> to replace the object's content.
It is more clear to call either L<stringify()|Mail::Field/"Accessors"> or L<parse()|Mail::Field/""Fake" constructors"> directly, because
this method does not add additional processing.
=back
=head1 DETAILS
=head2 SUB-CLASS PACKAGE NAMES
All sub-classes should be called Mail::Field::I<name> where I<name> is
derived from the tag using these rules.
=over 4
=item *
Consider a tag as being made up of elements separated by '-'
=item *
Convert all characters to lowercase except the first in each element, which
should be uppercase.
=item *
I<name> is then created from these elements by using the first
N characters from each element.
=item *
N is calculated by using the formula :-
int((7 + #elements) / #elements)
=item *
I<name> is then limited to a maximum of 8 characters, keeping the first 8
characters.
=back
For an example of this take a look at the definition of the
C<_header_pkg_name()> subroutine in C<Mail::Field>
=head1 DIAGNOSTICS
=over 4
=item Error: Undefined subroutine <method> called
Mail::Field objects use autoloading to compile new functionality.
Apparently, the method called is not implemented for the specific
class of the field object.
=back
=head1 SEE ALSO
This module is part of the MailTools distribution,
F<http://perl.overmeer.net/mailtools/>.
=head1 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 E<lt>aas@oslonett.noE<gt>.
Mail::Field::AddrList by Peter Orbaek E<lt>poe@cit.dkE<gt>.
Mail::Mailer and Mail::Send by Tim Bunce E<lt>Tim.Bunce@ig.co.ukE<gt>.
For other contributors see ChangeLog.
=head1 LICENSE
Copyrights 1995-2000 Graham Barr E<lt>gbarr@pobox.comE<gt> and
2001-2007 Mark Overmeer E<lt>perl@overmeer.netE<gt>.
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
See F<http://www.perl.com/perl/misc/Artistic.html>
|