sclass VoiceCRUD<A extends Concept> {
  Concept cc = db_mainConcepts();
  Class<A> conceptClass;
  S concept, concepts; // singular & plural of what we are managing
  
  *(Class<A> *conceptClass, S conceptName) {
    concept = conceptName;
    concepts = plural(concepts); }
  
  S answer(S s) null {
    new Matches m;
    if (match("how many \*concepts*/", s))
      ret str(countConcepts(cc, A));
    if (match("delete \*concept*/ *", s, m)) {
      S name = $1;
      setField(selected := null);
      A sc = findConceptWithName(name);
      if (sc == null)
ret format("\*firstToUpper(concept)*/ * not found", name);
      unregisterConcept(sc);
      addUndo(new UndoDeleteConcept(sc));
      ret format("Scenario * deleted", name);
    }
    if (match("new \*concept*/ *", s, m)) {
      S name = $1;
      A sc = conceptWhereCI(+name);
      if (sc != null)
        ret format("\*firstToUpper(concept)*/ * exists", name);
      setField(selected := uniqCI Scenario(+name));
      addUndo(new UndoCreateConcept(selected.id));
      ret format("\*firstToUpper(concept)*/ * created", name);
    }
    if (match("list \*concepts*/", s))
      ret or2(joinWithComma(collect name(list(Scenario))), "No \*concepts*/ defined");
    if (match("rename \*concept*/ * to *", s, m)) {
      S name1 = $1, name2 = $2;
      if (!eqic(name1, name2)
        && conceptWhereCI(conceptClass, name := name2) != null)
        ret format("A \*concept*/ named * exists", name2);
      A sc = findConceptWithName(name1);
      if (sc == null)
        ret format("\*firstToUpper(concept)*/ * not found", name1);
      addUndo(new UndoSetConceptField(sc.id, 'name, name1, name2));
      cset(sc, name := name2);
      ret format("\*firstToUpper(concept)*/ * renamed to *", name1, name2);
    }
  }
  
  swappable A findConceptWithName(S name) {
    ret conceptWhereCI(cc, conceptClass, +name);
  }
}