PHP: Value listing

Value listing

Both Pure Enums and Backed Enums implement an internal interface named UnitEnum. UnitEnum includes a static method cases(). cases() returns a packed array of all defined Cases in the order of declaration.

<?php

Suit::cases();
// Produces: [Suit::Hearts, Suit::Diamonds, Suit::Clubs, Suit::Spades]
?>

Manually defining a cases() method on an Enum will result in a fatal error.

Improve This Page

Learn How To Improve This Page • Submit a Pull Request • Report a Bug

＋add a note

User Contributed Notes 2 notes

down

theking2 at king dot ma ¶

2 years ago

As ::cases() creates a Iteratable it is possible to use it in a foreach loop. In combination with value backed enum this can result in very compact and very readable code:

<?php
/** Content Security Policy directives */
enum CspDirective: String {
  case Default = "default-src";
  case Image = "img-src";
  case Font = "font-src";
  case Script = "script-src";
  case Style = "style-src";
}

/** list all CSP directives */
foreach( CspSource::cases() as $directive ) {
  echo $directive-> value . PHP_EOL;
}
?>
Which results in:
default-src
img-src
font-src
script-src
style-src

down

-13

ratsimbasitraka at gmail dot com ¶

1 year ago

enum Priority {
    case Left;
    case Right;
}

// Does not work as default parameter
public function selectPriorities(array $priorities = Priority::cases()) {
    Priority::cases() // works here
}

＋add a note