Foo layout with a component definition

foo.php

$viewdefs['base']['layout']['foo'] = array(
   'components' => array(
      array(
         'layout' => 'header', //reference another definition
      ),
      array(
         'layout' => array( //directly include definition
            'components' => array(
               array(
                  'view' => 'title', //reference another definition
               ),
               array(
                  'view' => 'content', //reference another definition
               ),
            ),
            'type' => 'base',
            'name' => 'my-custom-main',
         ),
      ),
   ),
   'type' => 'foo',
   'name' => 'my-custom-page'
),