_global item_test << _proc(a_ds_collection)

   # recursively generate rope of current table and all joined tables

   top << a_ds_collection
   tables << rope.new()
   tables.add(top)
   s << stack.new()
   s.add(top)
   _loop
      _if s.size = 0 _then
         _leave
      _endif
      tab << s.next()
      _for f _over tab.visible_fields.fast_elements()
      _loop
         _if ~ f.is_join? _then
            _continue
         _endif
         t << f.result_table(tab.source_view)
         _if t _is _unset _then
            _continue  # skip text join field
         _elif ~ tables.includes?(t) _then
            tables.add(t)
            s.add(t)
         _endif
      _endloop
   _endloop

   # now generate items for tables

   s << internal_text_output_stream.new()
   _for t _over tables.fast_elements()
   _loop
      t.items_on(s)
   _endloop
   write(s.string)

_endproc