trusty (3) Moose::Exporter.3pm.gz
NAME
Moose::Exporter - make an import() and unimport() just like Moose.pm
VERSION
version 2.1005
SYNOPSIS
package MyApp::Moose;
use Moose ();
use Moose::Exporter;
Moose::Exporter->setup_import_methods(
with_meta => [ 'has_rw', 'sugar2' ],
as_is => [ 'sugar3', \&Some::Random::thing ],
also => 'Moose',
);
sub has_rw {
my ( $meta, $name, %options ) = @_;
$meta->add_attribute(
$name,
is => 'rw',
%options,
);
}
# then later ...
package MyApp::User;
use MyApp::Moose;
has 'name';
has_rw 'size';
thing;
no MyApp::Moose;
DESCRIPTION
This module encapsulates the exporting of sugar functions in a "Moose.pm"-like manner. It does this by
building custom "import" and "unimport" methods for your module, based on a spec you provide.
It also lets you "stack" Moose-alike modules so you can export Moose's sugar as well as your own, along
with sugar from any random "MooseX" module, as long as they all use "Moose::Exporter". This feature
exists to let you bundle a set of MooseX modules into a policy module that developers can use directly
instead of using Moose itself.
To simplify writing exporter modules, "Moose::Exporter" also imports "strict" and "warnings" into your
exporter module, as well as into modules that use it.
METHODS
This module provides two public methods:
Moose::Exporter->setup_import_methods(...)
When you call this method, "Moose::Exporter" builds custom "import" and "unimport" methods for your
module. The "import" method will export the functions you specify, and can also re-export functions
exported by some other module (like "Moose.pm"). If you pass any parameters for
Moose::Util::MetaRole, the "import" method will also call "Moose::Util::MetaRole::apply_metaroles"
and "Moose::Util::MetaRole::apply_base_class_roles" as needed, after making sure the metaclass is
initialized.
The "unimport" method cleans the caller's namespace of all the exported functions. This includes any
functions you re-export from other packages. However, if the consumer of your package also imports
those functions from the original package, they will not be cleaned.
Note that if any of these methods already exist, they will not be overridden, you will have to use
"build_import_methods" to get the coderef that would be installed.
This method accepts the following parameters:
• with_meta => [ ... ]
This list of function names only will be wrapped and then exported. The wrapper will pass the
metaclass object for the caller as its first argument.
Many sugar functions will need to use this metaclass object to do something to the calling
package.
• as_is => [ ... ]
This list of function names or sub references will be exported as-is. You can identify a
subroutine by reference, which is handy to re-export some other module's functions directly
by reference ("\&Some::Package::function").
If you do export some other package's function, this function will never be removed by the
"unimport" method. The reason for this is we cannot know if the caller also explicitly
imported the sub themselves, and therefore wants to keep it.
• trait_aliases => [ ... ]
This is a list of package names which should have shortened aliases exported, similar to the
functionality of aliased. Each element in the list can be either a package name, in which
case the export will be named as the last namespace component of the package, or an arrayref,
whose first element is the package to alias to, and second element is the alias to export.
• also => $name or \@names
This is a list of modules which contain functions that the caller wants to export. These
modules must also use "Moose::Exporter". The most common use case will be to export the
functions from "Moose.pm". Functions specified by "with_meta" or "as_is" take precedence
over functions exported by modules specified by "also", so that a module can selectively
override functions exported by another module.
"Moose::Exporter" also makes sure all these functions get removed when "unimport" is called.
• meta_lookup => sub { ... }
This is a function which will be called to provide the metaclass to be operated upon by the
exporter. This is an advanced feature intended for use by package generator modules in the
vein of MooseX::Role::Parameterized in order to simplify reusing sugar from other modules
that use "Moose::Exporter". This function is used, for example, to select the metaclass to
bind to functions that are exported using the "with_meta" option.
This function will receive one parameter: the class name into which the sugar is being
exported. The default implementation is:
sub { Class::MOP::class_of(shift) }
Accordingly, this function is expected to return a metaclass.
You can also provide parameters for "Moose::Util::MetaRole::apply_metaroles" and
"Moose::Util::MetaRole::base_class_roles". Specifically, valid parameters are "class_metaroles",
"role_metaroles", and "base_class_roles".
Moose::Exporter->build_import_methods(...)
Returns two code refs, one for "import" and one for "unimport".
Accepts the additional "install" option, which accepts an arrayref of method names to install into
your exporting package. The valid options are "import" and "unimport". Calling "setup_import_methods"
is equivalent to calling "build_import_methods" with "install => [qw(import unimport)]" except that
it doesn't also return the methods.
The "import" method is built using Sub::Exporter. This means that it can take a hashref of the form
"{ into => $package }" to specify the package it operates on.
Used by "setup_import_methods".
IMPORTING AND init_meta
If you want to set an alternative base object class or metaclass class, see above for details on how this
module can call Moose::Util::MetaRole for you.
If you want to do something that is not supported by this module, simply define an "init_meta" method in
your class. The "import" method that "Moose::Exporter" generates for you will call this method (if it
exists). It will always pass the caller to this method via the "for_class" parameter.
Most of the time, your "init_meta" method will probably just call "Moose->init_meta" to do the real work:
sub init_meta {
shift; # our class name
return Moose->init_meta( @_, metaclass => 'My::Metaclass' );
}
METACLASS TRAITS
The "import" method generated by "Moose::Exporter" will allow the user of your module to specify
metaclass traits in a "-traits" parameter passed as part of the import:
use Moose -traits => 'My::Meta::Trait';
use Moose -traits => [ 'My::Meta::Trait', 'My::Other::Trait' ];
These traits will be applied to the caller's metaclass instance. Providing traits for an exporting class
that does not create a metaclass for the caller is an error.
BUGS
See "BUGS" in Moose for details on reporting bugs.
AUTHOR
Moose is maintained by the Moose Cabal, along with the help of many contributors. See "CABAL" in Moose
and "CONTRIBUTORS" in Moose for details.
COPYRIGHT AND LICENSE
This software is copyright (c) 2013 by Infinity Interactive, Inc..
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5
programming language system itself.