=encoding utf8

=head1 NAME

Mail::Message::Field::Fast - one line of a message header

=head1 INHERITANCE

 Mail::Message::Field::Fast
   is a Mail::Message::Field
   is a Mail::Reporter

=head1 SYNOPSIS

  See Mail::Message::Field

=head1 DESCRIPTION

This is the faster, but less flexible implementation of a header field.
The data is stored in an array, and some hacks are made to speeds
things up.  Be gentle with me, and consider that each message contains
many of these lines, so speed is very important here.

Extends L<"DESCRIPTION" in Mail::Message::Field|Mail::Message::Field/"DESCRIPTION">.

=head1 OVERLOADED

Extends L<"OVERLOADED" in Mail::Message::Field|Mail::Message::Field/"OVERLOADED">.

=over 4

=item overload: B<'""'> stringification

Inherited, see L<Mail::Message::Field/"OVERLOADED">

=item overload: B<'0+'> numification

Inherited, see L<Mail::Message::Field/"OVERLOADED">

=item overload: B<'<=>'> numeric comparison

Inherited, see L<Mail::Message::Field/"OVERLOADED">

=item overload: B<bool> boolean

Inherited, see L<Mail::Message::Field/"OVERLOADED">

=item overload: B<cmp> string comparison

Inherited, see L<Mail::Message::Field/"OVERLOADED">

=back

=head1 METHODS

Extends L<"METHODS" in Mail::Message::Field|Mail::Message::Field/"METHODS">.

=head2 Constructors

Extends L<"Constructors" in Mail::Message::Field|Mail::Message::Field/"Constructors">.

=over 4

=item $obj-E<gt>B<clone>()

Inherited, see L<Mail::Message::Field/"Constructors">

=item $class-E<gt>B<new>(($line | $name, $body, [$attributes]), %options)

The constructor of this object does not follow the usual practise within
the L<Mail::Box|Mail::Box> suite: it does not use the constructor
L<Mail::Reporter::new()|Mail::Reporter/"Constructors">.

The method can be used in one of the following ways:

=over 4

=item * B<new>(C<$line>, C<%options>)

Pass a C<$line> as it could be found in a file: a (possibly folded) line
which is terminated by a new-line.

=item * B<new>(C<$name>, C<$body>, [C<$attributes>], C<%options>)

A set of values which shape the line.

=back

Create a new header field object.  Specify the whole C<$line> (encoded
octets) at once, and it will be split-up for you.  I case you already
have the parts of the header line, you may specify them separately as
C<$name> and field C<$body>.

In case you specify a single C<$body> object, or an ARRAY of objects,
these are processed to become suitable to fill a field, usually by simple
strification.  When you specify one or more L<Mail::Address|Mail::Address> objects, these
are transformed into a string using their C<format> method.  You may also
add one L<Mail::Message::Field|Mail::Message::Field>, whose body is taken.  In case of an array,
the elements are joined into one string with a comma.

The C<$attributes> can be exactly one string which may contain multiple attributes
at once, quoted and formatted as required in RFC2822.  As alternative,
list of key-value pairs can be used.  In this case, the values will get
quoted if needed and everything formatted as the protocol demands.
Improves base, see L<Mail::Message::Field/"Constructors">

» example: 

  my $mime = Mail::Message::Field->new(
    'Content-Type: text/plain; charset=US-ASCII');

  my $mime = Mail::Message::Field->new(
    'Content-Type' => 'text/plain; charset=US-ASCII');

  my $mime = Mail::Message::Field->new(
    'Content-Type' => 'text/plain', 'charset=US-ASCII');

  my $mime = Mail::Message::Field->new(
    'Content-Type' => 'text/plain', charset => 'Latin1');

  my $mime = Mail::Message::Field->new(
    To => Mail::Address->new('My', 'me@example.com');

  my $mime = Mail::Message::Field->new( Cc => [
    Mail::Address->new('You', 'you@example.com'),
    Mail::Address->new('His', 'he@example.com')
  ]);

But in practice, you can simply call

  my $head = Mail::Message::Head->new;
  $head->add( 'Content-Type' => 'text/plain', charset => 'utf8');

which implicitly calls this constructor (when needed).  You can specify
the same things for L<Mail::Message::Head::Complete::add()|Mail::Message::Head::Complete/"Access to the header"> as this
C<new> accepts.

=back

=head2 Attributes

Extends L<"Attributes" in Mail::Message::Field|Mail::Message::Field/"Attributes">.

=over 4

=item $obj-E<gt>B<Name>()

Inherited, see L<Mail::Message::Field/"Attributes">

=item $obj-E<gt>B<body>()

Inherited, see L<Mail::Message::Field/"Attributes">

=item $obj-E<gt>B<folded>()

Inherited, see L<Mail::Message::Field/"Attributes">

=item $obj-E<gt>B<foldedBody>( [$body] )

Inherited, see L<Mail::Message::Field/"Attributes">

=item $obj-E<gt>B<name>()

Inherited, see L<Mail::Message::Field/"Attributes">

=item $obj-E<gt>B<unfoldedBody>( [$body, [$wrap]] )

Inherited, see L<Mail::Message::Field/"Attributes">

=item $obj-E<gt>B<wellformedName>( [STRING] )

Inherited, see L<Mail::Message::Field/"Attributes">

=back

=head2 The field

Extends L<"The field" in Mail::Message::Field|Mail::Message::Field/"The field">.

=over 4

=item $any-E<gt>B<isStructured>( [$name] )

Inherited, see L<Mail::Message::Field/"The field">

=item $obj-E<gt>B<length>()

Inherited, see L<Mail::Message::Field/"The field">

=item $obj-E<gt>B<nrLines>()

Inherited, see L<Mail::Message::Field/"The field">

=item $obj-E<gt>B<print>( [$fh] )

Inherited, see L<Mail::Message::Field/"The field">

=item $obj-E<gt>B<size>()

Inherited, see L<Mail::Message::Field/"The field">

=item $obj-E<gt>B<string>( [$wrap] )

Inherited, see L<Mail::Message::Field/"The field">

=item $obj-E<gt>B<toDisclose>()

Inherited, see L<Mail::Message::Field/"The field">

=back

=head2 Access to the content

Extends L<"Access to the content" in Mail::Message::Field|Mail::Message::Field/"Access to the content">.

=over 4

=item $obj-E<gt>B<addresses>()

Inherited, see L<Mail::Message::Field/"Access to the content">

=item $obj-E<gt>B<attribute>( $name, [$value] )

Inherited, see L<Mail::Message::Field/"Access to the content">

=item $obj-E<gt>B<attributes>()

Inherited, see L<Mail::Message::Field/"Access to the content">

=item $obj-E<gt>B<comment>( [STRING] )

Inherited, see L<Mail::Message::Field/"Access to the content">

=item $any-E<gt>B<dateToTimestamp>(STRING)

Inherited, see L<Mail::Message::Field/"Access to the content">

=item $any-E<gt>B<stripCFWS>( [STRING] )

Inherited, see L<Mail::Message::Field/"Access to the content">

=item $obj-E<gt>B<study>()

Inherited, see L<Mail::Message::Field/"Access to the content">

=item $any-E<gt>B<toDate>( [$time] )

Inherited, see L<Mail::Message::Field/"Access to the content">

=item $obj-E<gt>B<toInt>()

Inherited, see L<Mail::Message::Field/"Access to the content">

=back

=head2 Parsing

Extends L<"Parsing" in Mail::Message::Field|Mail::Message::Field/"Parsing">.

=over 4

=item $obj-E<gt>B<consume>( $line | <$name,<$body|$objects>> )

Inherited, see L<Mail::Message::Field/"Parsing">

=item $obj-E<gt>B<defaultWrapLength>( [$length] )

Inherited, see L<Mail::Message::Field/"Parsing">

=item $any-E<gt>B<fold>( $name, $body, [$maxchars] )

Inherited, see L<Mail::Message::Field/"Parsing">

=item $obj-E<gt>B<setWrapLength>( [$length] )

Inherited, see L<Mail::Message::Field/"Parsing">

=item $obj-E<gt>B<stringifyData>(STRING|ARRAY|$objects)

Inherited, see L<Mail::Message::Field/"Parsing">

=item $obj-E<gt>B<unfold>(STRING)

Inherited, see L<Mail::Message::Field/"Parsing">

=back

=head2 Error handling

Extends L<"Error handling" in Mail::Message::Field|Mail::Message::Field/"Error handling">.

=over 4

=item $obj-E<gt>B<AUTOLOAD>()

Inherited, see L<Mail::Reporter/"Error handling">

=item $obj-E<gt>B<notImplemented>()

Inherited, see L<Mail::Reporter/"Error handling">

=back

=head2 Cleanup

Extends L<"Cleanup" in Mail::Message::Field|Mail::Message::Field/"Cleanup">.

=over 4

=item $obj-E<gt>B<DESTROY>()

Inherited, see L<Mail::Reporter/"Cleanup">

=back

=head1 DETAILS

Extends L<"DETAILS" in Mail::Message::Field|Mail::Message::Field/"DETAILS">.

=head1 DIAGNOSTICS

=over 4

=item Error: class $package does not implement method $method.

Fatal error: the specific C<$package> (or one of its superclasses) does not
implement this method where it should. This message means that some other
related classes do implement this method however the class at hand does
not.  Probably you should investigate this and probably inform the author
of the package.
Cast by C<notImplemented()>

=item Warning: field content is not numerical: $content

The numeric value of a field is requested (for instance the C<Lines> or
C<Content-Length> fields should be numerical), however the data contains
weird characters.
Cast by C<toInt()>

=item Error: field name too long (max $count), in '$name'.

It is not specified in the RFCs how long a field name can be, but
at least it should be a few characters shorter than the line wrap.
Cast by C<fold()>

=item Warning: illegal character in field name $name.

A new field is being created which does contain characters not permitted
by the RFCs.  Using this field in messages may break other e-mail clients
or transfer agents, and therefore mutulate or extinguish your message.
Cast by C<consume()>

=back

=head1 SEE ALSO

This module is part of Mail-Message version 4.05,
built on April 10, 2026. Website: F<http://perl.overmeer.net/mailbox/>

=head1 LICENSE

For contributors see file ChangeLog.

This software is copyright (c) 2001-2026 by Mark Overmeer.

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

