Attributes

Simple usage of attributes brought by PHP8.

Install

composer require authanram/attributes

Usage

Create an attribute class for any purpose, casting, mapping, etc.

<?php

namespace AwesomeProject\Attributes;

#[Attribute(Attribute::TARGET_PROPERTY)]
AwesomeAttribute
{
    /**
     * @param mixed ...$args // ['whatever', 'data']
     */
    public funtion __construct(mixed ...$args)
    {}
    
    /**
     * @param object $context   // Instance of AwesomeProject\AwesomeClass
     * @param string $name      // 'foo' (The name of the property the attribute belongs to)
     * @param mixed ...$args    // ['your', 'args']
     * 
     * @return void
     */
    public function handle(object $context, string $name, mixed ...$args)
    {
    }
    
    /**
     * @param mixed $old // 'qux'
     * 
     * @return string
     */
    public function value(mixed $old): string
    {
        return 'bar';
    }
}

Use your Attribute (somewhere)

For e.g.

<?php

namespace AwesomeProject;

use Authanram\Attributes;

AwesomeClass
{
    #[Attributes\AwesomeAttribute('whatever', 'data')]
    public string $foo = 'qux';
    
    public function __construct()
    {
        new Attributes($this, 'your', 'args');
    }
}

Create an Instance

$instance = new \AwesomeProject\AwesomeClass();

$instance->foo; // 'bar'

Some Words

The methods handle and value will only be called if present. Means if the constructor (and arguments) plus of one these methods will fit to your needs, the other one can be omitted.

Under the hood an instance of the attribute class will be created and the methods handle and value will be called, if present.

The return value of the method value will be assigned the corresponding property. Through the arguments $context and $name, passed to the method handle, you'll be able to assign a value manually to the property the attribute belongs to, e.g. $context->{$name} = 'qux';

In general, this should equip you with some low level tools to utilize attributes in your code.

Testing

vendor/bin/pest