// adds default constructor to classes with "persistable" modifier
// also allows "persistent"
svoid tok_persistableClasses(LS tok) {
  int i;
  
  while((i = jfind_any(tok, tokCondition {
    for (int j = i+1; isIdentifier(_get(tok, j)); j += 2)
      if (eqGet(tok, j, "class"))
        true;
    false;
  }, "persistable", "persistent")) >= 0) {
    int iClass = indexOf(tok, "class", i);
    S className = get(tok, iClass+2);
    int idx = indexOf(tok, iClass, "{");
    int j = findEndOfBracketPart(tok, idx);
    L<S> contents = subList(tok, idx+1, j);
    bool hasDefaultConstructor = tok_hasDefaultConstructor(contents, className);
    printVars_str("tok_persistableClasses: ", +hasDefaultConstructor, +className);
    if (!hasDefaultConstructor)
      tokAppend_reTok(tok, idx, "\n  *() {}");
    clearTokens_reTok(tok, i, i+2); // drop persistable keyword
  }
}