# phpman > perldoc > Moose::Cookbook::Basics::Document_AugmentAndInner

## NAME
    [Moose::Cookbook::Basics::Document_AugmentAndInner](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3ACookbook%3A%3ABasics%3A%3ADocumentAugmentAndInner/markdown) - The augment modifier, which turns normal
    method overriding "inside-out"

## VERSION
    version 2.2200

## SYNOPSIS
      package [Document::Page](https://www.chedong.com/phpMan.php/perldoc/Document%3A%3APage/markdown);
      use Moose;

      has 'body' => ( is => 'rw', isa => 'Str', default => sub {''} );

      sub create {
          my $self = shift;
          $self->open_page;
          inner();
          $self->close_page;
      }

      sub append_body {
          my ( $self, $appendage ) = @_;
          $self->body( $self->body . $appendage );
      }

      sub open_page  { (shift)->append_body('<page>') }
      sub close_page { (shift)->append_body('</page>') }

      package [Document::PageWithHeadersAndFooters](https://www.chedong.com/phpMan.php/perldoc/Document%3A%3APageWithHeadersAndFooters/markdown);
      use Moose;

      extends '[Document::Page](https://www.chedong.com/phpMan.php/perldoc/Document%3A%3APage/markdown)';

      augment 'create' => sub {
          my $self = shift;
          $self->create_header;
          inner();
          $self->create_footer;
      };

      sub create_header { (shift)->append_body('<header/>') }
      sub create_footer { (shift)->append_body('<footer/>') }

      package TPSReport;
      use Moose;

      extends '[Document::PageWithHeadersAndFooters](https://www.chedong.com/phpMan.php/perldoc/Document%3A%3APageWithHeadersAndFooters/markdown)';

      augment 'create' => sub {
          my $self = shift;
          $self->create_tps_report;
          inner();
      };

      sub create_tps_report {
          (shift)->append_body('<report type="tps"/>');
      }

      # <page><header/><report type="tps"/><footer/></page>
      my $report_xml = TPSReport->new->create;

## DESCRIPTION
    This recipe shows how the "augment" method modifier works. This modifier reverses the normal
    subclass to parent method resolution order. With an "augment" modifier the *least* specific
    method is called first. Each successive call to "inner" descends the inheritance tree, ending at
    the most specific subclass.

    The "augment" modifier lets you design a parent class that can be extended in a specific way.
    The parent provides generic wrapper functionality, and the subclasses fill in the details.

    In the example above, we've created a set of document classes, with the most specific being the
    "TPSReport" class.

    We start with the least specific class, "[Document::Page](https://www.chedong.com/phpMan.php/perldoc/Document%3A%3APage/markdown)". Its create method contains a call to
    "inner()":

      sub create {
          my $self = shift;
          $self->open_page;
          inner();
          $self->close_page;
      }

    The "inner" function is exported by "Moose", and is like "super" for augmented methods. When
    "inner" is called, Moose finds the next method in the chain, which is the "augment" modifier in
    "[Document::PageWithHeadersAndFooters](https://www.chedong.com/phpMan.php/perldoc/Document%3A%3APageWithHeadersAndFooters/markdown)". You'll note that we can call "inner" in our modifier:

      augment 'create' => sub {
          my $self = shift;
          $self->create_header;
          inner();
          $self->create_footer;
      };

    This finds the next most specific modifier, in the "TPSReport" class.

    Finally, in the "TPSReport" class, the chain comes to an end:

      augment 'create' => sub {
          my $self = shift;
          $self->create_tps_report;
          inner();
      };

    We do call the "inner" function one more time, but since there is no more specific subclass,
    this is a no-op. Making this call means we can easily subclass "TPSReport" in the future.

## CONCLUSION
    The "augment" modifier is a powerful tool for creating a set of nested wrappers. It's not
    something you will need often, but when you do, it is very handy.

## AUTHORS
    *   Stevan Little <<stevan@cpan.org>>

    *   Dave Rolsky <<autarch@urth.org>>

    *   Jesse Luehrs <<doy@cpan.org>>

    *   Shawn M Moore <<sartak@cpan.org>>

    *   יובל קוג'מן (Yuval Kogman) <<nothingmuch@woobling.org>>

    *   Karen Etheridge <<ether@cpan.org>>

    *   Florian Ragwitz <<rafl@debian.org>>

    *   Hans Dieter Pearcey <<hdp@cpan.org>>

    *   Chris Prather <<chris@prather.org>>

    *   Matt S Trout <<mstrout@cpan.org>>

## COPYRIGHT AND LICENSE
    This software is copyright (c) 2006 by Infinity Interactive, Inc.

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