Enumeration : Example

// #PS:90
// psn > a30 > a80
scala> // Use Enumeration to create a group of Constant just like

scala> // in any other language

scala> 

scala> // Example 1

scala> object WeekDay extends Enumeration {
     | val Mon, Tue, Wed, Thu, Fri, Sat, Sun = Value
     | }
defined module WeekDay

scala> import WeekDay._
import WeekDay._

scala> def isWorkingDay(d: Value) = ! (d == Sat || d == Sun)
isWorkingDay: (d: WeekDay.Value)Boolean

scala> WeekDay.values filter isWorkingDay foreach println
Mon
Tue
Wed
Thu
Fri

scala> 

scala> //Example 2

scala> object WeekDay extends Enumeration {
     | //Give alias for 'Value' type as 'WeekDay'
     | type WeekDay = Value  
     | //In this line 'Value' is a method, whereas the 'Value'
     | //used in the previous line represents a Type
     | //val Mon, Tue, Wed, Thu, Fri, Sat, Sun = Value("Day") 
     | val Mon, Tue, Wed, Thu, Fri, Sat, Sun = Value 
     | }
defined module WeekDay

scala> import WeekDay._
import WeekDay._

scala> def isWorkingDay(d: WeekDay) = ! (d == Sat || d == Sun)
isWorkingDay: (d: WeekDay.WeekDay)Boolean

scala> WeekDay.values filter isWorkingDay foreach{x => 
     |   println(x, x.id)
     | }
(Mon,0)
(Tue,1)
(Wed,2)
(Thu,3)
(Fri,4)