my $vars = {
        title=> = 'Template Test' ,
        site_name => 'TEST Home Page',
        header  => {
                date    => 'Jan 1, 2008',
                author  => 'Me, myself and I',
        },
        row     => [
                {
                        first   => 'row 1 value 1',
                        second  => 'row 1 value 2',
                },
                {
                        first   => 'row 2 value 1',
                        second  => 'row 2 value 2',
                },
        ],
        footer  => {
                modified        => 'Aug 31, 2006',
        },
    } ;

##</code><code>##

  $vars = { %$vars, # Copy in the old values, then add to them..
        header  => { ...