Mouse(3pm) User Contributed Perl Documentation Mouse(3pm)
NAME
Mouse - Moose minus the antlers
VERSION
This document describes Mouse version v2.5.10
SYNOPSIS
package Point;
use Mouse; # automatically turns on strict and warnings
has 'x' => (is => 'rw', isa => 'Int');
has 'y' => (is => 'rw', isa => 'Int');
sub clear {
my($self) = @_;
$self->x(0);
$self->y(0);
}
__PACKAGE__->meta->make_immutable();
package Point3D;
use Mouse;
extends 'Point';
has 'z' => (is => 'rw', isa => 'Int');
after 'clear' => sub {
my($self) = @_;
$self->z(0);
};
__PACKAGE__->meta->make_immutable();
DESCRIPTION
Moose is a postmodern object system for Perl5. Moose is wonderful.
Unfortunately, Moose has a compile-time penalty. Though significant
progress has been made over the years, the compile time penalty is a
non-starter for some very specific applications. If you are writing a
command-line application or CGI script where startup time is essential,
you may not be able to use Moose (we recommend that you instead use
persistent Perl executing environments like "FastCGI" for the latter,
if possible).
Mouse is a Moose compatible object system, which aims to alleviate this
penalty by providing a subset of Moose's functionality.
We're also going as light on dependencies as possible. Mouse currently
has no dependencies except for building/testing modules. Mouse also
works without XS, although it has an XS backend to make it much faster.
Moose Compatibility
Compatibility with Moose has been the utmost concern. The sugary
interface is highly compatible with Moose. Even the error messages are
taken from Moose. The Mouse code just runs its test suite 4x faster.
The idea is that, if you need the extra power, you should be able to
run "s/Mouse/Moose/g" on your codebase and have nothing break. To that
end, we have written Any::Moose which will act as Mouse unless Moose is
loaded, in which case it will act as Moose. Since Mouse is a little
sloppier than Moose, if you run into weird errors, it would be worth
running:
ANY_MOOSE=Moose perl your-script.pl
to see if the bug is caused by Mouse. Moose's diagnostics and
validation are also better.
See also Mouse::Spec for compatibility and incompatibility with Moose.
Mouse Extentions
Please don't copy MooseX code to MouseX. If you need extensions, you
really should upgrade to Moose. We don't need two parallel sets of
extensions!
If you really must write a Mouse extension, please contact the Moose
mailing list or #moose on IRC beforehand.
KEYWORDS
"$object->meta -> Mouse::Meta::Class"
Returns this class' metaclass instance.
"extends superclasses"
Sets this class' superclasses.
"before (method|methods|regexp) => CodeRef"
Installs a "before" method modifier. See "before" in Moose.
"after (method|methods|regexp) => CodeRef"
Installs an "after" method modifier. See "after" in Moose.
"around (method|methods|regexp) => CodeRef"
Installs an "around" method modifier. See "around" in Moose.
"has (name|names) => parameters"
Adds an attribute (or if passed an arrayref of names, multiple
attributes) to this class. Options:
"is => ro|rw|bare"
The is option accepts either rw (for read/write), ro (for read
only) or bare (for nothing). These will create either a read/write
accessor or a read-only accessor respectively, using the same name
as the $name of the attribute.
If you need more control over how your accessors are named, you can
use the "reader", "writer" and "accessor" options, however if you
use those, you won't need the is option.
"isa => TypeName | ClassName"
Provides type checking in the constructor and accessor. The
following types are supported. Any unknown type is taken to be a
class check (e.g. "isa => 'DateTime'" would accept only DateTime
objects).
Any Item Bool Undef Defined Value Num Int Str ClassName
Ref ScalarRef ArrayRef HashRef CodeRef RegexpRef GlobRef
FileHandle Object
For more documentation on type constraints, see
Mouse::Util::TypeConstraints.
"does => RoleName"
This will accept the name of a role which the value stored in this
attribute is expected to have consumed.
"coerce => Bool"
This will attempt to use coercion with the supplied type constraint
to change the value passed into any accessors or constructors. You
must have supplied a type constraint in order for this to work. See
Moose::Cookbook::Basics::Recipe5 for an example.
"required => Bool"
Whether this attribute is required to have a value. If the
attribute is lazy or has a builder, then providing a value for the
attribute in the constructor is optional.
"init_arg => Str | Undef"
Allows you to use a different key name in the constructor. If
undef, the attribute can't be passed to the constructor.
"default => Value | CodeRef"
Sets the default value of the attribute. If the default is a
coderef, it will be invoked to get the default value. Due to quirks
of Perl, any bare reference is forbidden, you must wrap the
reference in a coderef. Otherwise, all instances will share the
same reference.
"lazy => Bool"
If specified, the default is calculated on demand instead of in the
constructor.
"predicate => Str"
Lets you specify a method name for installing a predicate method,
which checks that the attribute has a value. It will not invoke a
lazy default or builder method.
"clearer => Str"
Lets you specify a method name for installing a clearer method,
which clears the attribute's value from the instance. On the next
read, lazy or builder will be invoked.
"handles => HashRef|ArrayRef|Regexp"
Lets you specify methods to delegate to the attribute. ArrayRef
forwards the given method names to method calls on the attribute.
HashRef maps local method names to remote method names called on
the attribute. Other forms of "handles", such as RoleName and
CodeRef, are not yet supported.
"weak_ref => Bool"
Lets you automatically weaken any reference stored in the
attribute.
Use of this feature requires Scalar::Util!
"trigger => CodeRef"
Any time the attribute's value is set (either through the accessor
or the constructor), the trigger is called on it. The trigger
receives as arguments the instance, and the new value.
"builder => Str"
Defines a method name to be called to provide the default value of
the attribute. "builder => 'build_foo'" is mostly equivalent to
"default => sub { $_[0]->build_foo }".
"auto_deref => Bool"
Allows you to automatically dereference ArrayRef and HashRef
attributes in list context. In scalar context, the reference is
returned (NOT the list length or bucket status). You must specify
an appropriate type constraint to use auto_deref.
"lazy_build => Bool"
Automatically define the following options:
has $attr => (
# ...
lazy => 1
builder => "_build_$attr",
clearer => "clear_$attr",
predicate => "has_$attr",
);
"confess(message) -> BOOM"
"confess" in Carp for your convenience.
"blessed(value) -> ClassName | undef"
"blessed" in Scalar::Util for your convenience.
MISC
import
Importing Mouse will default your class' superclass list to
Mouse::Object. You may use "extends" to replace the superclass list.
unimport
Please unimport Mouse ("no Mouse") so that if someone calls one of the
keywords (such as "extends") it will break loudly instead breaking
subtly.
DEVELOPMENT
Here is the repo: <https://github.com/gfx/p5-Mouse>.
You can build, test, and release it with Minilla.
cpanm Minilla
minil build
minil test
minil release
Note that Build.PL and README.md are generated by Minilla, so you
should not edit them. Edit minil.toml and lib/Mouse.pm instead.
SEE ALSO
Mouse::Role
Mouse::Spec
Moose
Moose::Manual
Moose::Cookbook
Class::MOP
Moo
AUTHORS
Shawn M Moore <sartak at gmail.com>
Yuval Kogman <nothingmuch at woobling.org>
tokuhirom
Yappo
wu-lee
Goro Fuji (gfx) <gfuji@cpan.org>
with plenty of code borrowed from Class::MOP and Moose
BUGS
All complex software has bugs lurking in it, and this module is no
exception. Please report any bugs to
<https://github.com/gfx/p5-Mouse/issues>.
COPYRIGHT AND LICENSE
Copyright (c) 2008-2010 Infinity Interactive, Inc.
http://www.iinteractive.com/
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
perl v5.36.0 2022-10-20 Mouse(3pm)
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