NAME

Class::CompoundMethods - Create methods from components

VERSION

0.04

SYNOPSIS

package Object;
use Class::CompoundMethods 'append_method';

# This installs both versioning_hook and auditing_hook into the
# method Object::pre_insert.
append_method( pre_insert => "versioning_hook" );
append_method( pre_insert => "auditing_hook" );

DESCRIPTION

This allows you to install more than one method into a single method name. I created this so I could install both versioning and auditing hooks into another module's object space. So instead of creating a single larger method which incorporates the functionality of both hooks I created append_method()/insert_method() to install a wrapper method as needed.

If only one method is ever installed into a space, it is installed directly with no wrapper. Once there are two or more components, a hook method is installed which will call each component in order.

PUBLIC METHODS

append_method( $method_name, $method )

append_method( $method_name, $method );

This function takes two parameters - a method name and the method to install.

$method_name may be fully qualified. If not, Class::CompoundMethods looks for your method in your current package.

append_method( 'Object::something', ... );
append_method( 'something', ... );

$method may be either a code reference or a method name. It may be fully qualified.

append_method( ..., sub { ... } );
append_method( ..., \ &some_hook );
append_method( ..., 'Object::some_hook' );
append_method( ..., 'some_hook' );

prepend_method( $method_name, $method )

prepend_method( $method_name, $method );

This function takes two parameters - a method name and the method to install.

$method_name may be fully qualified. If not, Class::CompoundMethods looks for your method in your current package.

prepend_method( 'Object::something', ... );
prepend_method( 'something', ... );

$method may be either a code reference or a method name. It may be fully qualified.

prepend_method( ..., sub { ... } );
prepend_method( ..., \ &some_hook );
prepend_method( ..., 'Object::some_hook' );
prepend_method( ..., 'some_hook' );

EXAMPLES

Example 1

use Class::CompoundMethods qw(append_method);

# This installs both versioning_hook and auditing_hook into the
# method Object::pre_insert.
append_method( 'Object::something' => \ &versioning_hook );

package Object;
prepend_method( 'something' => \ &auditing_hook );

Example 2

package GreenPartyDB::Database;
use Class::CompoundMethods qw(append_method);

my @versioned_tables = ( ... );
my @audited_tables = ( ... );

for my $table ( @versioned_tables ) {
   my $package = __PACKAGE__ . "::" . $table;
   append_method( $package . "::pre_insert", \ &versioning_hook );
   append_method( $package . "::pre_update", \ &versioning_hook );
   append_method( $package . "::pre_delete", \ &versioning_hook );
}

for my $table ( @audited_tables ) {
   my $package = __PACKAGE__ . "::" . $table;
   append_method( $package . "::pre_insert", \ &auditing_hook );
   append_method( $package . "::pre_update", \ &auditing_hook );
   append_method( $package . "::pre_delete", \ &auditing_hook );
}

EXPORT

This class optionally exports the append_method and prepend_method functions. It also uses the ':all' tag.

use Class::CompoundMethods qw( append_method );

use Class::CompoundMethods qw( :all );

COPYRIGHT & LICENSE

Copyright (c) 2005 Joshua ben Jore All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

AUTHOR

"Joshua ben Jore" <jjore@cpan.org>

SEE ALSO

RFC Class::AppendMethods http://www.perlmonks.org/index.pl?node_id=252199

Installing chained methods http://www.perlmonks.org/index.pl?node_id=251908