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Shorthand for common attribute options
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MooseX::AttributeShortcuts - Shorthand for common attribute options


version 0.008


    package Some::Class;

    use Moose;
    use MooseX::AttributeShortcuts;

    # same as:
    #   is => 'ro', lazy => 1, init_arg => undef, builder => '_build_foo'
    has foo => (is => 'lazy');

    # same as: is => 'ro', writer => '_set_foo'
    has foo => (is => 'rwp');

    # same as: is => 'ro', builder => '_build_bar'
    has bar => (is => 'ro', builder => 1);

    # same as: is => 'ro', clearer => 'clear_bar'
    has bar => (is => 'ro', clearer => 1);

    # same as: is => 'ro', predicate => 'has_bar'
    has bar => (is => 'ro', predicate => 1);

    # works as you'd expect for "private": predicate => '_has_bar'
    has _bar => (is => 'ro', predicate => 1);

    # extending? Use the "Shortcuts" trait alias
    extends 'Some::OtherClass';
    has '+bar' => (traits => [Shortcuts], builder => 1, ...);

    # or...
    package Some::Other::Class;

    use Moose;
    use MooseX::AttributeShortcuts -writer_prefix => '_';

    # same as: is => 'ro', writer => '_foo'
    has foo => (is => 'rwp');


Ever find yourself repeatedly specifing writers and builders, because there's no good shortcut to specifying them? Sometimes you want an attribute to have a read-only public interface, but a private writer. And wouldn't it be easier to just say "builder => 1" and have the attribute construct the canonical "_build_$name" builder name for you?

This package causes an attribute trait to be applied to all attributes defined to the using class. This trait extends the attribute option processing to handle the above variations.


This package automatically applies an attribute metaclass trait. Unless you want to change the defaults, you can ignore the talk about "prefixes" below.


If you're extending a class and trying to extend its attributes as well, you'll find out that the trait is only applied to attributes defined locally in the class. This package exports a trait shortcut function "Shortcuts" that will help you apply this in the attribute definition:

    has '+something' => (traits => [Shortcuts], ...);


We accept two parameters on the use of this module; they impact how builders and writers are named.


    use MooseX::::AttributeShortcuts -writer_prefix => 'prefix';

The default writer prefix is '_set_'. If you'd prefer it to be something else (say, '_'), this is where you'd do that.

NOTE: If you're using 0.001, this is a change. Sorry about that :\


    use MooseX::::AttributeShortcuts -builder_prefix => 'prefix';

The default builder prefix is '_build_', as this is what lazy_build does, and what people in general recognize as build methods.


Unless specified here, all options defined by Moose::Meta::Attribute and Class::MOP::Attribute remain unchanged.

Want to see additional options? Ask, or better yet, fork on GitHub and send a pull request.

For the following, "$name" should be read as the attribute name; and the various prefixes should be read using the defaults.

is => 'rwp'

Specifing is => 'rwp' will cause the following options to be set:

    is     => 'ro'
    writer => "_set_$name"

is => 'lazy'

Specifing is => 'lazy' will cause the following options to be set:

    is       => 'ro'
    builder  => "_build_$name"
    init_arg => undef
    lazy     => 1

is => 'lazy', default => ...

Specifing is => 'lazy' and a default will cause the following options to be set:

    is       => 'ro'
    init_arg => undef
    lazy     => 1

Note that this is the same as the prior option, but is included / phrased in this way in a (successful, I hope) attempt at clarity.

builder => 1

Specifying builder => 1 will cause the following options to be set:

    builder => "_build_$name"

clearer => 1

Specifying clearer => 1 will cause the following options to be set:

    clearer => "clear_$name"

or, if your attribute name begins with an underscore:

    clearer => "_clear$name"

(that is, an attribute named "_foo" would get "_clear_foo")

predicate => 1

Specifying predicate => 1 will cause the following options to be set:

    predicate => "has_$name"

or, if your attribute name begins with an underscore:

    predicate => "_has$name"

(that is, an attribute named "_foo" would get "_has_foo")

trigger => 1

Specifying trigger => 1 will cause the attribute to be created with a trigger that calls a named method in the class with the options passed to the trigger. By default, the method name the trigger calls is the name of the attribute prefixed with "_trigger_".

e.g., for an attribute named "foo" this would be equivalent to:

    trigger => sub { shift->_trigger_foo(@_) }

For an attribute named "_foo":

    trigger => sub { shift->_trigger__foo(@_) }

This naming scheme, in which the trigger is always private, is the same as the builder naming scheme (just with a different prefix).


All complex software has bugs lurking in it, and this module is no exception.

Please report any bugs to "", or through the web interface at <>.


Chris Weyl <>


This software is Copyright (c) 2011 by Chris Weyl.

This is free software, licensed under:

  The GNU Lesser General Public License, Version 2.1, February 1999
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