NAME
MooseX::AttributeShortcuts - Shorthand for common attribute options
VERSION
This document describes version 0.015 of MooseX::AttributeShortcuts -
released August 26, 2012 as part of MooseX-AttributeShortcuts.
SYNOPSIS
package Some::Class;
use Moose;
use MooseX::AttributeShortcuts;
# same as:
# is => 'ro', lazy => 1, 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');
DESCRIPTION
Ever find yourself repeatedly specifying 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_$name" builder name for you?
This package causes an attribute trait to be applied to all attributes
defined to the using class. This trait extends the attribute option
processing to handle the above variations.
USAGE
This package automatically applies an attribute metaclass trait. Unless
you want to change the defaults, you can ignore the talk about
"prefixes" below.
EXTENDING A CLASS
If you're extending a class and trying to extend its attributes as well,
you'll find out that the trait is only applied to attributes defined
locally in the class. This package exports a trait shortcut function
"Shortcuts" that will help you apply this to the extended attribute:
has '+something' => (traits => [Shortcuts], ...);
PREFIXES
We accept two parameters on the use of this module; they impact how
builders and writers are named.
-writer_prefix
use MooseX::::AttributeShortcuts -writer_prefix => 'prefix';
The default writer prefix is '_set_'. If you'd prefer it to be something
else (say, '_'), this is where you'd do that.
-builder_prefix
use MooseX::::AttributeShortcuts -builder_prefix => 'prefix';
The default builder prefix is '_build_', as this is what lazy_build
does, and what people in general recognize as build methods.
NEW ATTRIBUTE OPTIONS
Unless specified here, all options defined by Moose::Meta::Attribute and
Class::MOP::Attribute remain unchanged.
Want to see additional options? Ask, or better yet, fork on GitHub and
send a pull request.
For the following, "$name" should be read as the attribute name; and the
various prefixes should be read using the defaults.
is => 'rwp'
Specifying "is => 'rwp'" will cause the following options to be set:
is => 'ro'
writer => "_set_$name"
is => 'lazy'
Specifying "is => 'lazy'" will cause the following options to be set:
is => 'ro'
builder => "_build_$name"
lazy => 1
NOTE: Since 0.009 we no longer set "init_arg => undef" if no "init_arg"
is explicitly provided. This is a change made in parallel with Moo,
based on a large number of people surprised that lazy also made one's
"init_def" undefined.
is => 'lazy', default => ...
Specifying "is => 'lazy'" and a default will cause the following options
to be set:
is => 'ro'
lazy => 1
default => ... # as provided
That is, if you specify "is => 'lazy'" and also provide a "default",
then we won't try to set a builder, as well.
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).
builder => sub { ... }
Passing a coderef to builder will cause that coderef to be installed in
the class this attribute is associated with the name you'd expect, and
"builder => 1" to be set.
e.g., in your class,
has foo => (is => 'ro', builder => sub { 'bar!' });
...is effectively the same as...
has foo => (is => 'ro', builder => '_build_foo');
sub _build_foo { 'bar!' }
SOURCE
The development version is on github at
<http://github.com/RsrchBoy/moosex-attributeshortcuts> and may be cloned
from <git://github.com/RsrchBoy/moosex-attributeshortcuts.git>
BUGS
Please report any bugs or feature requests on the bugtracker website
https://github.com/RsrchBoy/moosex-attributeshortcuts/issues
When submitting a bug or request, please include a test-file or a patch
to an existing test-file that illustrates the bug or desired feature.
AUTHOR
Chris Weyl <cweyl@alumni.drew.edu>
COPYRIGHT AND LICENSE
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