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    <h3>Editing: LazyOption.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php

/*
 * Copyright 2012 Johannes M. Schmitt &lt;schmittjoh@gmail.com&gt;
 *
 * Licensed under the Apache License, Version 2.0 (the &quot;License&quot;);
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an &quot;AS IS&quot; BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

namespace PhpOption;

use Traversable;

/**
 * @template T
 *
 * @extends Option&lt;T&gt;
 */
final class LazyOption extends Option
{
    /** @var callable(mixed...):(Option&lt;T&gt;) */
    private $callback;

    /** @var array&lt;int, mixed&gt; */
    private $arguments;

    /** @var Option&lt;T&gt;|null */
    private $option;

    /**
     * @template S
     * @param callable(mixed...):(Option&lt;S&gt;) $callback
     * @param array&lt;int, mixed&gt;              $arguments
     *
     * @return LazyOption&lt;S&gt;
     */
    public static function create($callback, array $arguments = []): self
    {
        return new self($callback, $arguments);
    }

    /**
     * @param callable(mixed...):(Option&lt;T&gt;) $callback
     * @param array&lt;int, mixed&gt;              $arguments
     */
    public function __construct($callback, array $arguments = [])
    {
        if (!is_callable($callback)) {
            throw new \InvalidArgumentException('Invalid callback given');
        }

        $this-&gt;callback = $callback;
        $this-&gt;arguments = $arguments;
    }

    public function isDefined(): bool
    {
        return $this-&gt;option()-&gt;isDefined();
    }

    public function isEmpty(): bool
    {
        return $this-&gt;option()-&gt;isEmpty();
    }

    public function get()
    {
        return $this-&gt;option()-&gt;get();
    }

    public function getOrElse($default)
    {
        return $this-&gt;option()-&gt;getOrElse($default);
    }

    public function getOrCall($callable)
    {
        return $this-&gt;option()-&gt;getOrCall($callable);
    }

    public function getOrThrow(\Exception $ex)
    {
        return $this-&gt;option()-&gt;getOrThrow($ex);
    }

    public function orElse(Option $else)
    {
        return $this-&gt;option()-&gt;orElse($else);
    }

    public function ifDefined($callable)
    {
        $this-&gt;option()-&gt;forAll($callable);
    }

    public function forAll($callable)
    {
        return $this-&gt;option()-&gt;forAll($callable);
    }

    public function map($callable)
    {
        return $this-&gt;option()-&gt;map($callable);
    }

    public function flatMap($callable)
    {
        return $this-&gt;option()-&gt;flatMap($callable);
    }

    public function filter($callable)
    {
        return $this-&gt;option()-&gt;filter($callable);
    }

    public function filterNot($callable)
    {
        return $this-&gt;option()-&gt;filterNot($callable);
    }

    public function select($value)
    {
        return $this-&gt;option()-&gt;select($value);
    }

    public function reject($value)
    {
        return $this-&gt;option()-&gt;reject($value);
    }

    /**
     * @return Traversable&lt;T&gt;
     */
    public function getIterator(): Traversable
    {
        return $this-&gt;option()-&gt;getIterator();
    }

    public function foldLeft($initialValue, $callable)
    {
        return $this-&gt;option()-&gt;foldLeft($initialValue, $callable);
    }

    public function foldRight($initialValue, $callable)
    {
        return $this-&gt;option()-&gt;foldRight($initialValue, $callable);
    }

    /**
     * @return Option&lt;T&gt;
     */
    private function option(): Option
    {
        if (null === $this-&gt;option) {
            /** @var mixed */
            $option = call_user_func_array($this-&gt;callback, $this-&gt;arguments);
            if ($option instanceof Option) {
                $this-&gt;option = $option;
            } else {
                throw new \RuntimeException(sprintf('Expected instance of %s', Option::class));
            }
        }

        return $this-&gt;option;
    }
}
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