howto.pod

source of perl for linux application,

=head1 NAME

CPANPLUS::Shell::Default::Plugins::HOWTO -- documentation on how to write your own plugins

=head1 SYNOPSIS

    package CPANPLUS::Shell::Default::Plugins::MyPlugin;
    
    ### return command => method mapping
    sub plugins { ( myplugin1 => 'mp1', myplugin2 => 'mp2' ) }
    
    ### method called when the command '/myplugin1' is issued
    sub mp1 { .... }

    ### method called when the command '/? myplugin1' is issued
    sub mp1_help { return "Help Text" }
    
=head1 DESCRIPTION

This pod text explains how to write your own plugins for 
C<CPANPLUS::Shell::Default>. 

=head1 HOWTO

=head2 Registering Plugin Modules

Plugins are detected by using C<Module::Pluggable>. Every module in
the C<CPANPLUS::Shell::Default::Plugins::*> namespace is considered a
plugin, and is attempted to be loaded.

Therefor, any plugin must be declared in that namespace, in a corresponding
C<.pm> file.

=head2 Registering Plugin Commands

To register any plugin commands, a list of key value pairs must be returned
by a C<plugins> method in your package. The keys are the commands you wish 
to register, the values are the methods in the plugin package you wish to have
called when the command is issued.

For example, a simple 'Hello, World!' plugin:

    package CPANPLUS::Shell::Default::Plugins::HW;
    
    sub plugins { return ( helloworld => 'hw' ) };
    
    sub hw { print "Hello, world!\n" }
    
When the user in the default shell now issues the C</helloworld> command,
this command will be dispatched to the plugin, and it's C<hw> method will
be called

=head2 Registering Plugin Help

To provide usage information for your plugin, the user of the default shell
can type C</? PLUGIN_COMMAND>. In that case, the function C<PLUGIN_COMMAND_help>
will be called in your plugin package.

For example, extending the above example, when a user calls C</? helloworld>,
the function C<hw_help> will be called, which might look like this:

    sub hw_help { "    /helloworld      # prints "Hello, world!\n" }
    
If you dont provide a corresponding _help function to your commands, the
default shell will handle it gracefully, but the user will be stuck without
usage information on your commands, so it's considered undesirable to omit
the help functions.

=head2 Arguments to Plugin Commands

Any plugin function will receive the following arguments when called, which
are all positional:

=over 4

=item Classname -- The name of your plugin class

=item Shell     -- The CPANPLUS::Shell::Default object

=item Backend   -- The CPANPLUS::Backend object

=item Command   -- The command issued by the user

=item Input     -- The input string from the user

=item Options   -- A hashref of options provided by the user

=back

For example, the following command:

    /helloworld bob --nofoo --bar=2 joe
    
Would yield the following arguments:    

    sub hw {
        my $class   = shift;    # CPANPLUS::Shell::Default::Plugins::HW
        my $shell   = shift;    # CPANPLUS::Shell::Default object
        my $cb      = shift;    # CPANPLUS::Backend object
        my $cmd     = shift;    # 'helloworld'
        my $input   = shift;    # 'bob joe'
        my $opts    = shift;    # { foo => 0, bar => 2 }

        ....
    }


=head1 BUG REPORTS

Please report bugs or other issues to E<lt>[e-mail]<gt>.

=head1 AUTHOR

This module by Jos Boumans E<lt>[e-mail]<gt>.

=head1 COPYRIGHT

The CPAN++ interface (of which this module is a part of) is copyright (c) 
2001 - 2007, Jos Boumans E<lt>[e-mail]<gt>. All rights reserved.

This library is free software; you may redistribute and/or modify it 
under the same terms as Perl itself.

=head1 SEE ALSO

L<CPANPLUS::Shell::Default>, L<CPANPLUS::Shell>, L<cpanp>

=cut

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