Tag Type C++ code (built in to libHForm/
Attributes None.
Contained Tags VarNone or more.
ActionOne or more. Should come after all Var tags.
Related Tags Var tags that do not need to be passed to handlers or saved to files should go in the Private section instead. Both of these sections are ignored unless they occur within the Head section.

A Public section looks a lot like a Private section except that there are Action tags at the end.
    {Var name="lamp_state" loc="test.par"}
    {Var name="filter_pos"}
    {Var name="lamp_name"}
    {Var name="filter_name"}
    {Var name="retry"}

    {Action id=apply} 
      ...(see examples for Action)...
    {Action id=another_unique_id}