(PHP 8)
The Stringable interface denotes a class as having a __toString() method. Unlike most interfaces, Stringable is implicitly present on any class that has the magic __toString() method defined, although it can and should be declared explicitly.
Its primary value is to allow functions to type check against the union
type string|Stringable
to accept either a string primitive
or an object that can be cast to a string.
Example #1 Basic Stringable Usage
<?phpclass IPv4Address implements Stringable { private string $oct1; private string $oct2; private string $oct3; private string $oct4; public function __construct(string $oct1, string $oct2, string $oct3, string $oct4) { $this->oct1 = $oct1; $this->oct2 = $oct2; $this->oct3 = $oct3; $this->oct4 = $oct4; } public function __toString(): string { return "$this->oct1.$this->oct2.$this->oct3.$this->oct4"; }}function showStuff(string|Stringable $value) { // A Stringable will get converted to a string here by calling // __toString. print $value;}$ip = new IPv4Address('123', '234', '42', '9');showStuff($ip);?>
The above example will output something similar to:
123.234.42.9