// fields: type + name
sS tok_genEqualsAndHashCode(S className, LPairS fields) {
  S argName = "o";
  while (pairsB(fields).contains(argName)) argName = "_" + argName;
  StringBuilder buf = new("\n\npublic bool equals(O \*argName*/) {\n");
  if (empty(fields))
    buf.append("ret \*argName*/ instanceof " + className + ";\n");
  else
    buf.append([[if (!\*argName*/ instanceof ]] + className + [[) false;
    ]] + className + [[ x = cast ]] + argName + [[;
    ret ]] + join(" && ", map(fields, func(Pair<S> p) -> S {
      // TODO: use == for primitive fields
      "eq(" + p.b + ", x." + p.b + ")"
    })) + ";\n");
  buf.append("}\n");
  
  buf.append([[
  public int hashCode() {
    int h = ]] + hashCode(className) + [[;
    ]] + concatMap_strings(fields, func(Pair<S> p) {
      "h = boostHashCombine(h, _hashCode(" + p.b + [[));
    ]]}) + [[ret h;
  }
  ]]);
  ret str(buf);
}