---
name: "CPANPLUS::Shell::Default::Plugins::HOWTO"
section: "3perl"
platform: "linux"
package: "perl-doc"
version: "5.14.2-21+deb7u3"
release: "Debian 7 (Wheezy)"
platforms: ["linux"]
url: "https://new.carta.tech/CPANPLUS::Shell::Default::Plugins::HOWTO"
---

# CPANPLUS::Shell::Default::Plugins::HOWTO(3perl)

## NAME

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

## 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" }
```

## DESCRIPTION

This pod text explains how to write your own plugins for  `"CPANPLUS::Shell::Default"`.

## HOWTO

### Registering Plugin Modules

Plugins are detected by using `"Module::Pluggable"`. Every module in the `"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 `".pm"` file.

### Registering Plugin Commands

To register any plugin commands, a list of key value pairs must be returned by a `"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 `"/helloworld"` command, this command will be dispatched to the plugin, and its `"hw"` method will be called

### Registering Plugin Help

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

For example, extending the above example, when a user calls `"/? helloworld"`, the function `"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.

### Arguments to Plugin Commands

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

- Classname Ω- The name of your plugin class

  - Shell Ω- The CPANPLUS::Shell::Default object

  - Backend Ω- The CPANPLUS::Backend object

  - Command Ω- The command issued by the user

  - Input Ω- The input string from the user

  - Options Ω- A hashref of options provided by the user

  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 }
        ....
    }
```

## BUG REPORTS

Please report bugs or other issues to \<bug-cpanplus@rt.cpan.org\<gt\>.

## AUTHOR

This module by Jos Boumans \<kane@cpan.org\>.

## COPYRIGHT

The CPAN++ interface (of which this module is a part of) is copyright (c)  2001 - 2007, Jos Boumans \<kane@cpan.org\>. All rights reserved.

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

## SEE ALSO

CPANPLUS::Shell::Default, CPANPLUS::Shell, cpanp