struct tvision_info {
  TObject *tobj;
};

struct tvision_info*
tvision_info_from_magic(SV *objref, int flags) {
  ...
}

##</code><code>##

TYPEMAP
TObject*    O_TObject
TView*      O_TView
TButton*    O_TButton

INPUT
O_TObject
  $var= tvision_info_from_magic($arg, OR_DIE)->tobj;

O_TView
  $var= dynamic_cast<TView*>(tvision_info_from_magic($arg, OR_DIE)->tobj);
  if (!$var) croak("Not an instance of TView");

O_TButton
  $var= dynamic_cast<TButton*>(tvision_info_from_magic($arg, OR_DIE)->tobj);
  if (!$var) croak("Not an instance of TButton");

##</code><code>##

bool
focus(view)
  TView* view
  CODE:
    RETVAL= view->focus();
  OUTPUT:
    RETVAL

##</code><code>##

template <T> void tvision_obj_from_magic(T *dest, SV *objref, int flags) {
  struct tvision_info* tinfo= tvision_info_from_magic(objref, flags);
  T typed= tinfo->tobj? dynamic_cast<T>(tinfo->tobj) : NULL;
  if ((flags & OR_DIE) && !typed) croak("Wrong type of object");
  *dest= typed;
}

##</code><code>##

O_TButton
  tvision_obj_from_magic(&$var, $arg, OR_DIE);

##</code><code>##

TYPEMAP
TObject*    O_TObject
TView*      O_TObject
TButton*    O_TObject

INPUT
O_TObject
  $var= dynamic_cast<$type>(tvision_info_from_magic($arg, OR_DIE)->tobj);
  if (!$var) croak("Object is not a $type");