Chaining Static Methods in PHP?

Question

Is it possible to chain static methods together using a static class? Say I wanted to do something like this:

$value = TestClass::toValue(5)::add(3)::subtrac         


        

Answer 1

Here's another way without going through a getInstance method (tested on PHP 7.x):

class TestClass
{
    private $result = 0;

    public function __call($method, $args)
    {
        return $this->call($method, $args);
    }

    public static function __callStatic($method, $args)
    {
        return (new static())->call($method, $args);
    }

    private function call($method, $args)
    {
        if (! method_exists($this , '_' . $method)) {
            throw new Exception('Call undefined method ' . $method);
        }

        return $this->{'_' . $method}(...$args);
    }

    private function _add($num)
    {
        $this->result += $num;

        return $this;
    }

    private function _subtract($num)
    {
        $this->result -= $num;

        return $this;
    }

    public function result()
    {
        return $this->result;
    }
}

The class can be used as following:

$res1 = TestClass::add(5)
    ->add(3)
    ->subtract(2)
    ->add(8)
    ->result();

echo $res1 . PHP_EOL; // 14

$res2 = TestClass::subtract(1)->add(10)->result();
echo $res2 . PHP_EOL; // 9