Enums

Enums is a language extension that adds an enumerated type support to ActionScript3.

The enumerated type consist of a set of named values. For example, the four suits in a deck of playing cards may be four enumerators named SPADES, CLUBS, DIAMONDS, HEARTS, belonging to an enumerated type named Cardsuit.

##Syntax

enum enumTypeName [extends enum] [implements Interface] { ENUM1 [, ENUM2, ENUM3 … ] }

Enum class declaration can be created the from the right-click menu on the package after importing the enum language to a project. The syntax is similar to a class declaration statement. Enumerated members should be written in capital letters and separated by commas.

public enum Cardsuit extends <none> implements <none> {
  SPADES, 
  CLUBS, 
  DIAMONDS, 
  HEARTS 

  public function Cardsuit() { 
    // enum constructor
  } 
}

Constructor

Enum constructor, as well as any other function, can receive arguments. Besides the constructor, an enumerator can have another methods, as well as any other class.

public enum Cardsuit extends <none> implements <none> {
  SPADES(13), 
  CLUBS(13), 
  DIAMONDS(13), 
  HEARTS(13)

  public function Cardsuit(amount : int) { 
    // this will be executed on instance creation 
    _amount = amount; // create field and assign a parameter 
  }

  private var _amount : int;

  public function get amount ( ) : int { 
    // getter
    return _amount;
  } 
}

enumTypeName.ENUM[.properties]

An enumerator can be referred from another class using an expression, containing enumerated type name, enumerator and its properties.

public function Main() {
  Cardsuit.SPADES; 
  Cardsuit.CLUBS.amount;
} 

.name operation

Name operation is often used when it needs to get enumerators from any other method.

public function Main() { 
  myGetEnum(Cardsuit.DIAMONDS);
} 

public function myGetEnum(myEnum : Cardsuit) : void { 
  myEnum.name; // myEnum.name = DIAMONDS 
  myEnum.amount; // DIAMONDS.amount value
}

enumTypeName.NAMES

Cardsuit.NAMES; // list, that stores all enums' name of Cardsuit class

switch enumType case ENUM

Using switch statement is a good practice with enums, because case expression allows to use short form to refer to an enumerator.

switch (myEnum) { 
  case SPADES : 
    break; 
  case CLUBS : 
    break; 
  case DIAMONDS : 
    break; 
  case HEARTS : 
    break; 
}