svoid philosophyBot1_bool(PhilosophyBot1 bot) {
  // native predicates now work in rule lhs too
  bot.addNativePredicate("true", map -> true);
  bot.addNativePredicate("$x = $y",
    map -> eqic($x(map), $y(map)));
  bot.addNativePredicate("$x != $y",
    map -> {
      S x = $x(map), y = $y(map);
      print("equality check: " + x + " / " + y);
      ret !eqic(x, y);
    });
}