ArrayOption.php

<?php

class ArrayOptionNoSuchElementException extends ErrorException {}

class ArrayOption
{
    private $v;

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

    public function __get($name)
    {
        if (is_array($this->v)) {
            $v = array_key_exists($name, $this->v) ? $this->v[$name] : null;
        }
        else {
            $v = $this->v;
        }
        return new self($v);
    }

    public function get()
    {
        if (is_null($this->v)) {
            throw new ArrayOptionNoSuchElementException();
        }
        return $this->v;
    }

    public function getOrElse($default)
    {
        if (is_null($this->v)) {
            return $default;
        }
        return $this->v;
    }
}

//$xarr = new ArrayOption(['hoge' => ['fuga' => 'piyo']]);
//var_dump($xarr->hoge->get());
//var_dump($xarr->hoge->fuga->get());
//// var_dump($xarr->foo->get()); ArrayOptionError
//
//var_dump($xarr->hoge->getOrElse('nakatta'));
//var_dump($xarr->hoge->fuga->getOrElse('hogehoge'));
//var_dump($xarr->foo->getOrElse('nakatta'));
//
//foreach ($xarr->hoge->get() as $k => $v) {
//    echo "\$k: $k, \$v: $v\n";
//}