effect Writer {
    fun hello() -> Unit;
    fun world() -> Unit;
}

pub fun main() ! Io -> Unit {
    try {
        hello!();
        Writer.world!();
        print!("\n");
        return;
    } handle Writer {
        fun hello() {
            print!("wrong hello");
            resume;
        }

        fun world() {
            print!("world");
            resume;
        }
    }
}

fun hello() ! Io -> Unit {
    try {
        Writer.hello!();
        print!(", ");
        return;
    } handle Writer {
        fun hello() {
            print!("hello");
            resume;
        }

        fun world() {
            print!("wrong world");
            resume;
        }
    }
}