# remex(:unique_choice_lister)
# $

def_slotted_exemplar(:unique_choice_lister,{},{:choice_lister})
$

_method unique_choice_lister.activate_on(a_field,
   a_model, an_action, _optional max_size, string_selector, select_mode)

   ## Populates the choice list with unique values for a_field.
   ## Max_size specifies the maximum number of records to search
   ## (default 512).  Use only on physical or derived fields.

   f << a_field
   max << max_size.default(512)
   t << f.owner.active_collection
   s << sorted_set.new(max)
   n << 0
   _for e _over t.fast_elements()
   _loop
      v << e.perform(f.name)
      _if v _is _unset _then
         _continue
      _endif
      s.add(v)
      n +<< 1
      _if n = max _then
         _leave
      _endif
   _endloop
   _super.activate_on(s.as_simple_vector(), a_model, an_action,
                      string_selector, select_mode)

_endmethod