Scala Enumerations
This repository demonstrates the pros and cons of scala.Enumeration and examines alternative structures.
Structure
src/main/java - two examples of Java enum classes.
src/main/scala - examples of various enumerations:
-
scala-lang-enum.scala - the
scala.Enumerationexample -
klang_enum_weekday.scala and klang_enum_planets.scala - examples using the DIY Enum class.
-
sealed-enum-weekday.scala and sealed-enum-planets.scala - examples using sealed traits (or abstract class) and class objects (or classes).
macros - an SBT project containing the macros used in the sealed-enum-planets.scala example.
Running
enum-eval (master)$ sbt
> run
[info] Compiling 5 Scala sources and 2 Java sources to enum-eval/target/scala-2.11/classes...
[warn] enum-eval/src/main/scala/klang-enum-planets.scala:67: match may not be exhaustive.
[warn] It would fail on the following inputs: $anon(), $anon(), $anon(), $anon(), $anon(), $anon(), $anon(), $anon()
[warn] planet match {
[warn] ^
[warn] enum-eval/src/main/scala/klang-enum-weekday.scala:67: match may not be exhaustive.
[warn] It would fail on the following inputs: $anon(), $anon(), $anon(), $anon(), $anon(), $anon(), $anon()
[warn] def weekend(d: WeekDay.EnumVal) = d match {
[warn] ^
[warn] enum-eval/src/main/scala/sealed-enum-weekday.scala:32: match may not be exhaustive.
[warn] It would fail on the following inputs: Fri, Mon, Thu, Tue, Wed
[warn] def weekend(d: WeekDay.EnumVal) = d match {
[warn] ^
[warn] three warnings found
Multiple main classes detected, select one to run:
[1] SealedEnum
[2] KlangEnum
[3] SealedEnumPlanets
[4] KlangEnumPlanets
[5] ScalaLangEnumeration
Enter number: 3
[info] Running SealedEnumPlanets
TreeSet(Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune)
TreeSet(Jupiter, Saturn, Uranus, Neptune)
Your weight on Mercury is 26.4 kg
Your weight on Venus is 63.3 kg
Your weight on Earth is 70.0 kg
Your weight on Mars is 26.5 kg
Your weight on Jupiter is 177.1 kg
Your weight on Saturn is 74.6 kg
Your weight on Uranus is 63.4 kg
Your weight on Neptune is 79.7 kg
[success] Total time: 18 s, completed 23-Aug-2014 10:22:05
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