# This is called by foo() from the main application, just before
# to display the page
#
sub foo_view
{
    my $template   = shift;
    my $date       = shift;
    my $missing    = shift;
    my $invalid    = shift;

    $template->param( "missing_$_" => 1 ) for @$missing;
    $template->param( "invalid_$_" => 1 ) for @$invalid;

    # [...]

    return $template;
}