class Rule<T : Any>(
    val clazz: KClass<T>,
    val name: String,
    private val whenTrue: T.() -> Boolean,
    private val thenDo: Rule<T>.(T) -> Unit
) {
    fun fire(arg: T): Boolean {
        if (this.whenTrue(arg)) {
            thenDo(arg)
            return true
        }
        return false
    }
}

class RuleSet(private val rules: MutableList<Rule<*>>) {
    fun fire(arg: Any): Set<Rule<*>> = rules.filter { r -> (r as Rule<Any>).fire(arg) }.toSet()
}