sub dropdown_menu { # should generate only an HTML snippet of a menu
  #my ..arguments..;

 return  template 'form_menu.tt', { ...argument hash...  };
}
.
.
.

get '/' => sub { # generates the actual form that is used as [% content %] in the layout/main.tt template

  template 'some_form.tt', {
      menu1  => dropdown_menu(...parameters1...),
      menu2  => dropdown_menu(...parameters2...),
      radio1 => radio_group(...parameters3...),
      .
      . 
  }
}