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.

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User Contributed Notes 2 notes

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23
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
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0
anhaia dot gabriel at gmail dot com
2 months ago
If you want to get all the values of the Enum in a list of `string`, you might do something like this:

<?php

enum MyEnum: string
{
case
OPTION_A = 'option_a';
case
OPTION_B = 'option_b';
case
OPTION_C = 'option_c';

public static function
values(): array
{
return
array_map(fn ($case) => $case->value, self::cases());
}
}

?>
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