Moose::Cookbook::Basics::Recipe7(3) Making Moose fast with immutable


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


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.


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.


Dave Rolsky <[email protected]>


Copyright 2006-2010 by Infinity Interactive, Inc.


This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.