Dancer::ModuleLoader(3)

NAME
Dancer::ModuleLoader - dynamic module loading helpers for Dancer core components

VERSION
version 1.3522

SYNOPSIS
Taken directly from Dancer::Template::TemplateToolkit (which is core):

    die "Template is needed by Dancer::Template::TemplateToolkit"
      unless Dancer::ModuleLoader->load('Template');

    # we now have Template loaded

DESCRIPTION
Sometimes in Dancer core we need to use modules, but we don't want to declare them all in advance in compile-time. These could be because the specific modules provide extra features which depend on code that isn't (and shouldn't) be in core, or perhaps because we only want these components loaded in lazy style, saving loading time a bit. For example, why load Template (which isn't required by Dancer) when you don't use Dancer::Template::TemplateToolkit?

To do such things takes a bit of code for localizing $@ and "eval"ing. That code has been refactored into this module to help Dancer core developers.

Please only use this for Dancer core modules. If you're writing an external Dancer module (Dancer::Template::Tiny, Dancer::Session::Cookie, etc.), please simply ""use ModuleYouNeed"" in your code and don't use this module.

METHODS/SUBROUTINES

  load
Runs something like ""use ModuleYouNeed"" at runtime.

    use Dancer::ModuleLoader;
    ...
    Dancer::ModuleLoader->load('Something')
        or die "Couldn't load Something\n";

    # load version 5.0 or more
    Dancer::ModuleLoader->load('Something', '5.0')
        or die "Couldn't load Something\n";

    # load version 5.0 or more
    my ($res, $error) = Dancer::ModuleLoader->load('Something', '5.0');
    $res or die "Couldn't load Something : '$error'\n";

Takes in arguments the module name, and optionally the minimum version number required.

In scalar context, returns 1 if successful, 0 if not. In list context, returns 1 if successful, "(0, "error message")" if not.

If you need to give argument to the loading module, please use the method "load_with_params"

  require
Runs a ""require ModuleYouNeed"".

    use Dancer::ModuleLoader;
    ...
    Dancer::ModuleLoader->require('Something')
        or die "Couldn't require Something\n";
    my ($res, $error) = Dancer::ModuleLoader->require('Something');
    $res or die "Couldn't require Something : '$error'\n";

If you are unsure what you need ("require" or "load"), learn the differences between "require" and "use".

Takes in arguments the module name.

In scalar context, returns 1 if successful, 0 if not. In list context, returns 1 if successful, "(0, "error message")" if not.

  load_with_params
Runs a ""use ModuleYouNeed qw(param1 param2 ...)"".

    use Dancer::ModuleLoader;
    ...
    Dancer::ModuleLoader->load_with_params('Something', qw(param1 param2) )
        or die "Couldn't load Something with param1 and param2\n";

    my ($res, $error) = Dancer::ModuleLoader->load_with_params('Something', @params);
    $res or die "Couldn't load Something with @params: '$error'\n";

Takes in arguments the module name, and optionally parameters to pass to the import internal method.

In scalar context, returns 1 if successful, 0 if not. In list context, returns 1 if successful, "(0, "error message")" if not.

  use_lib
Runs a ""use lib qw(path1 path2)"" at run time instead of compile time.

    use Dancer::ModuleLoader;
    ...
    Dancer::ModuleLoader->use_lib('path1', @other_paths)
        or die "Couldn't perform use lib\n";

    my ($res, $error) = Dancer::ModuleLoader->use_lib('path1', @other_paths);
    $res or die "Couldn't perform use lib : '$error'\n";

Takes in arguments a list of path to be prepended to @INC, in a similar way than "use lib". However, this is performed at run time, so the list of paths can be generated and dynamic.

In scalar context, returns 1 if successful, 0 if not. In list context, returns 1 if successful, "(0, "error message")" if not.

  class_from_setting
Given a setting in Dancer::Config, composes the class it should be.

This is the function that translates:

    # in config.yaml
    template: "template_toolkit"

To the class:

    Dancer::Template::TemplateToolkit

Example:

    use Dancer::ModuleLoader;
    my $class = Dancer::ModuleLoader->class_from_setting(
        'Dancer::Template' => 'template_toolkit',
    );

    # $class == 'Dancer::Template::TemplateToolkit

    $class = Dancer::ModuleLoader->class_from_setting(
        'Dancer::Template' => 'tiny',
    );

    # class == 'Dancer::Template::Tiny

SEE ALSO
Module::Load, Module::New::Loader

AUTHOR
Dancer Core Developers

COPYRIGHT AND LICENSE
This software is copyright (c) 2010 by Alexis Sukrieh.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.