Manual Pages for UNIX Darwin command on man Mail::Field

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

NAME

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

SYNOPSIS

use Mail::Field;

$field = Mail::Field->new('Subject', 'some subject text');

print $field->tag,": ",$field->stringify,"\n";

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

DESCRIPTION

"Mail::Field" is a base class for packages that create and manipulate

fields from Email (and MIME) headers. Each different field will have

its own sub-class, defining its own interface.

This document describes the minimum interface that each sub-class

should provide, and also guidlines on how the field specific interface should be defined. CCOONNSSTTRRUUCCTTOORR

Mail::Field, and it's sub-classes define several methods which return

new objects. These can all be termed to be constructors.

new ( TAG [, STRING | OPTIONS ] )

The new constructor will create an object in the class which defines the field specified by the tag argument.

After creation of the object :-

If the tag argument is followed by a single string then the "parse" method will be called with this string. If the tag argument is followed by more than one arguments then the "create" method will be called with these arguments. extract ( TAG, HEAD [, INDEX ] ) This constuctor 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.

combine ( FIELDLIST )

This constructor takes as arguments a list of "Mail::Field"

objects, which should all be of the same sub-class, and creates a

new object in that same class.

This constructor is nor defined in "Mail::Field" as there is no

generic way to combine the various field types. Each sub-class

should define its own combine constructor, if combining is possible/allowed. MMEETTHHOODDSS parse set tag stringify

SUBCLASS PACKAGE NAMES

All sub-classes should be called Mail::Field::name where name is

derived from the tag using these rules.

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

+o Convert all characters to lowercase except the first in each element, which should be uppercase. +o name is then created from these elements by using the first N characters from each element.

+o N is calculated by using the formula :-

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

+o 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

"headerpkgname" subroutine in "Mail::Field"

AUTHOR Graham Barr. Maintained by Mark Overmeer