NAME
    Data::Inherited - Hierarchy-wide accumulation of list and hash results

SYNOPSIS
      package Foo;
      use base 'Data::Inherited';
      use constant PROPERTIES => (qw/name address/);

      package Bar;
      use base 'Foo';
      use constant PROPERTIES => (qw/age/);

      package main;
      my $bar = Bar->new;
      print "$_\n" for $bar->every_list('PROPERTIES');

    prints

      name
      address
      age

DESCRIPTION
    This is a mixin class. By inheriting from it you get two methods that
    are able to accumulate hierarchy-wide list and hash results.

METHODS
    "every_list(String $method_name, Bool ?$override_cache = 0)"
        Takes as arguments a method name (mandatory) and a boolean
        indicating whether to override the cache (optional, off by default)

        Causes every method in the object's hierarchy with the given name to
        be invoked. The resulting list is the combined set of results from
        all the methods, pushed together in top-to-bottom order
        (hierarchy-wise).

        "every_list()" returns a list in list context and an array reference
        in scalar context.

        The result is cached (per calling package) and the next time the
        method is called from the same package with the same method
        argument, the cached result is returned. This is to speed up method
        calls, because internally this module uses NEXT, which is quite
        slow. It is expected that "every_list()" is used for methods
        returning static lists (object defaults, static class definitions
        and such). If you want to override the caching mechanism, you can
        provide the optional second argument. The result is cached in any
        case.

        See the synopsis for an example.

    "every_hash(String $method_name, Bool ?$override_cache = 0)"
        Takes as arguments a method name (mandatory) and a boolean
        indicating whether to override the cache (optional, off by default)

        Causes every method in the object's hierarchy with the given name to
        be invoked. The resulting hash is the combined set of results from
        all the methods, overlaid in top-to-bottom order (hierarchy-wise).

        "every_hash()" returns a hash in list context and a hash reference
        in scalar context.

        The cache and the optional cache override argument work like with
        "every_list()".

        Example:

          package Person;
          use base 'Data::Inherited';

          sub new {
            my $class = shift;
            my $self = bless {}, $class;
            my %args = @_;
            %args = ($self->every_hash('DEFAULTS'), %args);
            $self->$_($args{$_}) for keys %args;
            $self;
          };

          sub DEFAULTS {
            first_name => 'John',
            last_name  => 'Smith',
          };

          package Employee;
          use base 'Person';

          sub DEFAULTS {
            salary => 10_000,
          }

          package LocatedEmployee;
          use base 'Employee';

          # Note: no default for address, but different salary

          sub DEFAULTS {
            salary     => 20_000,
            first_name => 'Johan',
          }

          package main;
          my $p = LocatedEmployee->new;

          # salary: 20000
          # first_name: Johan
          # last_name: Smith

    "flush_every_cache_by_key(String $key)"
        Deletes the cache entry for the given key.

BUGS AND LIMITATIONS
    No bugs have been reported.

    Please report any bugs or feature requests through the web interface at
    <http://rt.cpan.org>.

INSTALLATION
    See perlmodinstall for information and options on installing Perl
    modules.

AVAILABILITY
    The latest version of this module is available from the Comprehensive
    Perl Archive Network (CPAN). Visit <http://www.perl.com/CPAN/> to find a
    CPAN site near you. Or see
    <http://search.cpan.org/dist/Data-Domain-URI/>.

AUTHORS
    Marcel Grünauer, "<marcel@cpan.org>"

COPYRIGHT AND LICENSE
    Copyright 2004-2009 by the authors.

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