DOKK / manpages / debian 12 / libmoo-perl / Moo::Role.3pm.en
Moo::Role(3pm) User Contributed Perl Documentation Moo::Role(3pm)

Moo::Role - Minimal Object Orientation support for Roles

  package My::Role;
  use Moo::Role;
  use strictures 2;
  sub foo { ... }
  sub bar { ... }
  has baz => (
    is => 'ro',
  );
  1;

And elsewhere:

  package Some::Class;
  use Moo;
  use strictures 2;
  # bar gets imported, but not foo
  with 'My::Role';
  sub foo { ... }
  1;

"Moo::Role" builds upon Role::Tiny, so look there for most of the documentation on how this works (in particular, using "Moo::Role" also enables strict and warnings). The main addition here is extra bits to make the roles more "Moosey;" which is to say, it adds "has".

See "IMPORTED SUBROUTINES" in Role::Tiny for all the other subroutines that are imported by this module.

  has attr => (
    is => 'ro',
  );

Declares an attribute for the class to be composed into. See "has" in Moo for all options.

Moo::Role cleans up its own imported methods and any imports declared before the "use Moo::Role" statement automatically. Anything imported after "use Moo::Role" will be composed into consuming packages. A package that consumes this role:

  package My::Role::ID;
  use Digest::MD5 qw(md5_hex);
  use Moo::Role;
  use Digest::SHA qw(sha1_hex);
  requires 'name';
  sub as_md5  { my ($self) = @_; return md5_hex($self->name);  }
  sub as_sha1 { my ($self) = @_; return sha1_hex($self->name); }
  1;

..will now have a "$self->sha1_hex()" method available to it that probably does not do what you expect. On the other hand, a call to "$self->md5_hex()" will die with the helpful error message: "Can't locate object method "md5_hex"".

See "CLEANING UP IMPORTS" in Moo for more details.

See Moo for support and contact information.

See Moo for authors.

See Moo for the copyright and license.

2023-01-07 perl v5.36.0