Tutorial by Examples

Java-like enumerations can be created by extending Enumeration. object WeekDays extends Enumeration { val Mon, Tue, Wed, Thu, Fri, Sat, Sun = Value } def isWeekend(day: WeekDays.Value): Boolean = day match { case WeekDays.Sat | WeekDays.Sun => true case _ => false } isWeekend...

An alternative to extending Enumeration is using sealed case objects: sealed trait WeekDay object WeekDay { case object Mon extends WeekDay case object Tue extends WeekDay case object Wed extends WeekDay case object Thu extends WeekDay case object Fri extends WeekDay case objec...

This is just an extension on the sealed trait variant where a macro generates a set with all instances at compile time. This nicely omits the drawback that a developer can add a value to the enumeration but forget to add it to the allElements set. This variant especially becomes handy for large en...