Online PHP editor | refs for hGDts

<?php namespace igorw; class Past { private $value; private $pastValues; function __construct($value, array $pastValues = []) { $this->value = $value; $this->pastValues = $pastValues; } function map(callable $fn) { return $this->update($fn($this->value)); } function update($value) { return new Past($value, array_merge($this->pastValues, [$this->value])); } function get() { return array_rand($this->pastValues); } } $answer = new Past(42); $answer = $answer->map(function ($number) { return $number + 1; }); $answer = $answer->update(-3); $answer = $answer->map(function ($number) { return $number * -1; }); $answer = $answer->map(function ($number) { return $number * 3; }); $answer = $answer->update('completely new value, hehehe'); var_dump($answer->get());