PHP RFC: __toArray()

• Version: 0.1
• Date: 2019-08-28
• Author: Steven Wade, stevenwadejr@gmail.com
• Status: Draft
• First Published at: http://wiki.php.net/rfc/to-array

PHP contains many magic methods that give a class greater control over its interaction with the language. The methods __serialize() and __unserialize() give a class control over how it is serialized, __clone() allows control over how self copies are made, and __toString() allows a class to control how it is represented when converted to a string.

This RFC proposes to add a new magic method called __toArray() to allow a class to control how it is represented when converted to an array.

Example:

class Person
{
    protected $name;
    protected $email;
 
    public $foo = 'bar';
 
    public function __construct(string $name, string $email)
    {
        $this->name = $name;
        $this->email  = $email;
    }
 
    public function __toArray()
    {
        return [
            'name' => $this->name,
            'email'  => $this->email,
        ];
    }
}
 
$person = new Person('John Doe', 'j.doe@example.com');

Example usage:

print_r($person); // calls __toArray()
 
// Output
/*
Array
(
    [name] => John Doe
    [email] => j.doe@example.com
)
*/
 
$personArray = (array) $person; // casting triggers __toArray()

The example above shows the method __toArray() used in a type-casting context. This proposal would have objects implementing the __toArray() magic method called within any array context including type hinting and return types.

Similar to PHP's current implementation of __toString(), a copy of the given object's value as an array is made upon conversion.

Type Hinting

function foo(array $person) {
    var_dump($person);
}
 
// Output
/*
array(2) {
  ["name"]=>
  string(8) "John Doe"
  ["email"]=>
  string(17) "j.doe@example.com"
}
*/

Return Type

function bar(Person $person): array {
    return $person;
}
 
var_dump(bar($person));
 
// Output
/*
array(2) {
  ["name"]=>
  string(8) "John Doe"
  ["email"]=>
  string(17) "j.doe@example.com"
}
*/

array_* and built-in functions

The array operating functions listed on the Array Functions would first convert an object implementing the __toArray() method before continuing operations.

print_r(array_keys($person));
 
// Output
/*
Array
(
    [0] => first
    [1] => email
)
*/

This proposal does not allow accessing and setting values as you would in a normal array, that functionality remains with classes implementing the ArrayAccess interface. Discuss what the RFC does not cover (accessing and setting values as you would in a normal array.

What breaks, and what is the justification for it?

Next PHP version (target 8.0)

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This section details areas where the feature might be improved in future, but that are not currently proposed in this RFC.

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