Enums

An enumeration (enum) is a special or enumerated custom type that allows developers to have a fixed number of possible values.

Enumerations are available in many languages and are implemented in different features, but in PHP, they are a special kind of object.

Creating an enum

The keyword, enum, is used to declare an enumeration, followed by the name of the enum.

enum my_enum {
  case Case1;
  case Case2;
  case Case3;
}

Example

<?php
  enum Color {
    case Pink;
    case Blue;
    case Yellow;
  }

  // Functions and methods
  function choose_color(Color $color) { }
?>

By using the Color enumeration, now it is possible to enforce types when accepting or returning a value for color:

choose_color(Starter::Pink);
choose_color(Starter::Blue);
choose_color(Starter::Yellow);