class ConfirmationQuestion

class ConfirmationQuestion extends Question {
    
    /**
     * @param string $question        The question to ask to the user
     * @param bool   $default         The default answer to return, true or false
     * @param string $trueAnswerRegex A regex to match the "yes" answer
     */
    public function __construct(string $question, bool $default = true, string $trueAnswerRegex = '/^y/i') {
        parent::__construct($question, $default);
        $this->setNormalizer($this->getDefaultNormalizer());
    }
    
    /**
     * Returns the default answer normalizer.
     */
    private function getDefaultNormalizer() : callable {
        $default = $this->getDefault();
        $regex = $this->trueAnswerRegex;
        return function ($answer) use ($default, $regex) {
            if (\is_bool($answer)) {
                return $answer;
            }
            $answerIsTrue = (bool) preg_match($regex, $answer);
            if (false === $default) {
                return $answer && $answerIsTrue;
            }
            return '' === $answer || $answerIsTrue;
        };
    }

}