PHP 8 - Attributes Test

index.php

<?php

#[Attribute]
class Letter
{
    public const UPPER_CASE = 'UPPER_CASE';
    public const LOWER_CASE = 'LOWER_CASE';

    public function __construct(
        public string $modifier
    ) {}
}

function letterAnnotationProcessor(object $objectToModify): void
{
    $reflectionClass = new reflectionClass($objectToModify::class);
    $properties = $reflectionClass->getProperties();

    foreach ($properties as $property) {
        $propertyName = $property->getName();
        $attributes = $property->getAttributes(Letter::class);

        foreach ($attributes as $attribute) {
            $modifier = $attribute->newInstance()->modifier;
            $value = $objectToModify->$propertyName;

            $newValue = match ($modifier) {
                Letter::UPPER_CASE => strtoupper($value),
                Letter::LOWER_CASE => strtolower($value),
                default => $value,
            };

            $property->setValue($objectToModify, $newValue);
        }
    }
}

class Person
{
    #[Letter(Letter::UPPER_CASE)]
    public string $name;
}

$felipe = new Person();
$felipe->name = 'Felipe Renan Vieira';

var_dump($felipe);
letterAnnotationProcessor($felipe);
var_dump($felipe);

index2.php

<?php

interface IAttribute
{
    public static function action(object $object): void;
}

#[Attribute]
class Letter implements IAttribute
{
    public const UPPER_CASE = 'UPPER_CASE';
    public const LOWER_CASE = 'LOWER_CASE';

    public function __construct(
        public string $modifier
    ) {}

    public static function action(object $object): void
    {
        $reflectionClass = new reflectionClass($object::class);
        $properties = $reflectionClass->getProperties();

        foreach ($properties as $property) {
            $propertyName = $property->getName();
            $attributes = $property->getAttributes(self::class);

            foreach ($attributes as $attribute) {
                $modifier = $attribute->newInstance()->modifier;
                $value = $property->getValue($object);

                $newValue = match ($modifier) {
                    self::UPPER_CASE => strtoupper($value),
                    self::LOWER_CASE => strtolower($value),
                    default => $value,
                };

                $property->setValue($object, $newValue);
            }
        }
    }
}

function processAnnotations(array $items): void
{
    foreach ($items as $item) {
        $reflectionClass = new reflectionClass($item->object::class);
        $properties = $reflectionClass->getProperties();
        
        foreach ($properties as $property) {
            if ($property->getName() !== $item->property) continue;

            $attributes = $property->getAttributes();

            foreach ($attributes as $attribute) {
                $attributeClass = $attribute->getName();
                
                if (!in_array(IAttribute::class, class_implements($attributeClass))) continue;

                $attributeClass::action($item->object);
            }
        }
    }
}

class PersonUpper
{
    #[Letter(Letter::UPPER_CASE)]
    public string $name;

    public function setName(string $name)
    {
        $this->name = $name;
        processAnnotations([
            (object) [
                'object' => $this,
                'property' => 'name',
            ],
        ]);
    }
}

class PersonLower
{
    #[Letter(Letter::LOWER_CASE)]
    public string $name;

    public function setName(string $name)
    {
        $this->name = $name;
    }
}

$felipe = new PersonUpper();
$felipe->setName('Felipe');

$renan = new PersonLower();
$renan->setName('Felipe');

var_dump($felipe, $renan);

processAnnotations([
    (object) [
        'object' => $renan,
        'property' => 'name',
    ],
]);

var_dump($felipe, $renan);