recommended(3) Load recommended modules on demand when available


version 0.003


use recommended 'Foo::Bar', {
'Bar::Baz' => '1.23',
'Wibble' => '0.14',
if ( recommended->has( 'Foo::Bar' ) ) {
# do something with Foo::Bar
# default version required
if ( recommended->has( 'Wibble' ) ) {
# do something with Wibble if >= version 0.14
# custom version required
if ( recommended->has( 'Wibble', '0.10' ) ) {
# do something with Wibble if >= version 0.10


This module gathers a list of recommended modules and versions and provides means to check if they are available. It is a thin veneer around Module::Runtime.

There are two major benefits over using Module::Runtime directly:

  • Self-documents recommended modules together with versions at the top of your code, while still loading them on demand elsewhere.
  • Dies if a recommended module exists but fails to compile, but doesn't die if the module is missing or the version is insufficient. This is not something that Module::Runtime offers in a single subroutine.



    use recommended 'Foo::Bar', {
        'Bar::Baz' => '1.23',
        'Wibble'   => '0.14',

Scalar import arguments are treated as module names with a minimum required version of zero. Hash references are treated as module/minimum-version pairs. If you repeat, the later minimum version overwrites the earlier one.

The list of modules and versions are kept separate for each calling package.


    recommended->has( $module );
    recommended->has( $module, $alt_minimum_version );

The "has" method takes a module name and optional alternative minimum version requirement and returns true if the following conditions are met:

  • the module was recommended in the current package (via "use recommended")
  • the module can be loaded
  • the module meets the default or alternate minimum version

Otherwise, it returns false. If the module exists but fails to compile, an error is thrown. This avoids some edge-cases where things are left in an incomplete state or subsequent normal loads of the module by other packages get a misleading error.

The module is loaded without invoking the module's "import" method, as running import on an optional module at runtime is just weird.


Bugs / Feature Requests

Please report any bugs or feature requests through the issue tracker at <>. You will be notified automatically of any progress on your issue.

Source Code

This is open source software. The code repository is available for public review and contribution under the terms of the license.


  git clone


David Golden <[email protected]>


This software is Copyright (c) 2014 by David Golden.

This is free software, licensed under:

  The Apache License, Version 2.0, January 2004