=pod =head1 RECOMMENDATIONS Moose has a lot of features, and there's definitely more than one way to do it. However, we think that picking a subset of these features and using them consistently makes everyone's life easier. Of course, as with any list of "best practices", these are really just opinions. Feel free to ignore us. =head2 "No Moose" and Immutabilize We recommend that you end your Moose class definitions by removing the Moose sugar and making your class immutable. package Person; use Moose; # extends, roles, attributes, etc. # methods no Moose; __PACKAGE__->meta->make_immutable; 1; The "no Moose" bit is simply good code hygiene, and making classes immutable speeds up a lot of things, most notably object construction. =head2 Always call SUPER::BUILDARGS If you override the C method in your class, make sure to play nice and call C to handle cases you're not checking for explicitly.q The default C method in L handles both a list and hashref of named parameters correctly, and also checks for a I single argument. =head2 Don't Use the initializer Feature Don't know what we're talking about? That's fine. =head2 Use builder Instead of default Most of the Time. Builders can be inherited, they have explicit names, and they're just plain cleaner. However, I use a default when the default is a non-reference, I when the default is simply an empty reference of some sort. Also, keep your builder methods private. =head2 Use lazy_build Lazy is good, and often solves initialization ordering problems. It's also good for deferring work that may never have to be done. If you're going to be lazy, use I to save yourself some typing and standardize names. =head2 Consider Keeping clearers & predicates Private Does everyone I need to be able to clear an attribute? Probably not. Don't expose this functionality outside your class by default. Predicates are less problematic, but there's no reason to make your public API bigger than it has to be. =head2 Default to read-only, and Consider Keeping writers Private Making attributes mutable just means more complexity to account for in your program. The alternative to mutable state is to encourage users of your class to simply make new objects as needed. If you I make an attribute read-write, consider making the writer a separate private method. Narrower APIs are easy to maintain, and mutable state is trouble. =head2 Think Twice Before Changing an Attribute's Type in a Subclass Down this path lies great confusion. If the attribute is an object itself, at least make sure that it has the same interface as the type of object in the parent class. =head2 Use MooseX::AttributeHelpers Instead of auto_deref The C feature is a big troublesome. Directly exposing a complex attribute is ugly. Instead, consider using C to define an API that exposes those pieces of functionality that need exposing. Then you can expose just the functionality that you want. =head2 Namespace Your Types Use some sort of namespacing convention for type names. We recommend something like "MyApp.Type.Foo". I use "::" as the namespace separator, since that overlaps with actual class names. =head2 Coercion Instead of Unions Consider using a type coercion instead of a type union. This was covered at length in L. =head2 Define All Your Types in One Module Define all your types and coercions in one module. This was also covered in L. =head1 AUTHOR Dave Rolsky Eautarch@urth.orgE =head1 COPYRIGHT AND LICENSE Copyright 2009 by Infinity Interactive, Inc. L This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself. =cut