man Moose::Cookbook::Basics::Immutable (3): Making Moose fast by making your class immutable

VERSION

version 2.1605

SYNOPSIS

package Point;
use Moose;
has 'x' => ( isa => 'Int', is => 'ro' );
has 'y' => ( isa => 'Int', is => 'rw' );
__PACKAGE__->meta->make_immutable;

DESCRIPTION

The Moose metaclass API provides a "make_immutable()" method. Calling this method does two things to your class. First, it makes it faster. In particular, object construction and destruction are effectively ``inlined'' in your class, and no longer invoke the meta API.

Second, you can no longer make changes via the metaclass API, such as adding attributes. In practice, this won't be a problem, as you rarely need to do this after first loading the class.

CONCLUSION

We strongly recommend you make your classes immutable. It makes your code much faster, with a small compile-time cost. This will be especially noticeable when creating many objects.

AUTHORS

Stevan Little <[email protected]>
Dave Rolsky <[email protected]>
Jesse Luehrs <[email protected]>
Shawn M Moore <[email protected]>
יובל קוג'מן (Yuval Kogman) <[email protected]>
Karen Etheridge <[email protected]>
Florian Ragwitz <[email protected]>
Hans Dieter Pearcey <[email protected]>
Chris Prather <[email protected]>
Matt S Trout <[email protected]>

COPYRIGHT AND LICENSE