ClosureExample.php

<?php

/**
 * Created by PhpStorm.
 * User: APG
 * Date: 16.05.2020
 * Time: 15:18
 */
class ClosureExample
{
    private $value = 0;

    public function __construct(int $value)
    {
        $this->value = $value;
    }

    private function getValue()
    {
        return $this->value;
    }

    public function formatValue(Closure $closure)
    {
        # call - ìåòîä êëàññà Closure ñ ïàðàìåòðîì ÊÎÍÒÅÊÑÒ, âîçâðàùàåò óêàçàòåëü íà äàííûé êëàññ
        return $closure->call($this);
    }
}
/*
 * åñòü àíîíèìàÿ ôóíêöèÿ ãäå èñïîëüçóåì óêçààòü "ýòîò"
 * âíóòðè ôóíêöèè íåò óêàçàòåëÿ "ýòîò"
 *
 * ñîçäàäèì îáúåêò êëàññà Êëîçóðå
 * ïåðåäàåì àíîíèìíóþ ôóíêöèþ
 * ýòà ôóíêöèÿ àâòîìàòè÷åñêè îáîðà÷èâàåòñÿ â êëàññ Êëîæóð è ñòàíîâèòñÿ ýêçåìïëÿðîì êëàññà Êëîæóð
 * ó êîòîðîãî åñòü ìåòîä call ñ ïàðàìåòðîì - êîíòåêñò, òî åñòü âûçûâàåì àí.ôóíêöèþ â êîíòåêñòå êëàññà ÊëîæóðÝêçåìïë
 *
 */
$formatter = function () {
    return sprintf('format %01.2f$ ', $this->getValue());
};

$ex = new ClosureExample(5);
echo $ex->formatValue($formatter);