When are enums not a code smell?(softwareengineering.stackexchange.com)

    interface BoolLogic {
        fn bool(bool) -> Self;
        fn if(Self, Self, Self) -> Self;
    }
    struct Eval {
        value: Anything
    }
    implement BoolLogic for Eval {
        fn bool(value) -> Eval {
            Eval { value }
        }
        fn if(condition, consequent, alternate) -> Eval {
            if (conditon.value)
                consequent
            else
                alternate
        }
    }
    struct Print {
        text: String
    }
    implement BoolLogic for Print {
        fn bool(value) -> Print {
            let text = value.toString()
            Print { text }
        }
        fn if(condition, consequent, alternate) Print {
            let text = "if (" +
                condition.text +
                ") {" +
                consequent.text +
                "} else {" +
                alternate.text +
                "}"
            Print { text }
        }
    }
    interface NumLogic {
        fn num(int) -> Self
        fn add(Self, Self) -> Self
        fn eq(Self, Self) -> Self
    }
    implement NumLogic for Eval {
        fn num(value) -> {
            Eval { value }
        }
        fn add(left, right) -> Self {
            let value = left.value + right.value
            Eval { value }
        }
        fn eq(left, right) -> Self {
            let value = left.value == right.value
            Eval { value }
        }
    }
    fn munge<T: BoolLogic + NumLogic>() -> T {
        T.if(T.eq(T.add(T.nu.(2), T.num(2)), T.num(4)), T.num(42), T.num(0))
    }

  enum ToolLauncherMain {
    convertTheThing(this::doFoo, "Convert the bin to the dat"),
    sendSomeMessage(this::doBar, "Pass a message to the stuff-doer"),
    help(this::printHelp, "Print this message");

    private final Consumer<String[]> runner;
    private String description;

    public UtilRunner(Consumer<String[]> r, String desc) {
      runner = r;
      description = desc;
    }

    public static void main(String... args) {
      try {
        valueOf(args.length == 0 ? "help" : args[0]).runner.apply(args);
      } catch (IllegalArgumentException ex) {
        printHelp();
      }
    }

    private void printHelp() {
      for (var value : values()) {
        System.out.printf("%s - %s\n", value, value.description);
      }
    }

    // ...
  }