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

declare(strict_types=1);

/*
 * This file is part of the league/commonmark package.
 *
 * (c) Colin O'Dell &lt;colinodell@gmail.com&gt;
 *
 * Original code based on the CommonMark JS reference parser (https://bitly.com/commonmark-js)
 *  - (c) John MacFarlane
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace League\CommonMark\Renderer;

use League\CommonMark\Environment\EnvironmentInterface;
use League\CommonMark\Event\DocumentPreRenderEvent;
use League\CommonMark\Event\DocumentRenderedEvent;
use League\CommonMark\Node\Block\AbstractBlock;
use League\CommonMark\Node\Block\Document;
use League\CommonMark\Node\Node;
use League\CommonMark\Output\RenderedContent;
use League\CommonMark\Output\RenderedContentInterface;

final class HtmlRenderer implements DocumentRendererInterface, ChildNodeRendererInterface
{
    /** @psalm-readonly */
    private EnvironmentInterface $environment;

    public function __construct(EnvironmentInterface $environment)
    {
        $this-&gt;environment = $environment;
    }

    public function renderDocument(Document $document): RenderedContentInterface
    {
        $this-&gt;environment-&gt;dispatch(new DocumentPreRenderEvent($document, 'html'));

        $output = new RenderedContent($document, (string) $this-&gt;renderNode($document));

        $event = new DocumentRenderedEvent($output);
        $this-&gt;environment-&gt;dispatch($event);

        return $event-&gt;getOutput();
    }

    /**
     * {@inheritDoc}
     */
    public function renderNodes(iterable $nodes): string
    {
        $output = '';

        $isFirstItem = true;

        foreach ($nodes as $node) {
            if (! $isFirstItem &amp;&amp; $node instanceof AbstractBlock) {
                $output .= $this-&gt;getBlockSeparator();
            }

            $output .= $this-&gt;renderNode($node);

            $isFirstItem = false;
        }

        return $output;
    }

    /**
     * @return \Stringable|string
     *
     * @throws NoMatchingRendererException
     */
    private function renderNode(Node $node)
    {
        $renderers = $this-&gt;environment-&gt;getRenderersForClass(\get_class($node));

        foreach ($renderers as $renderer) {
            \assert($renderer instanceof NodeRendererInterface);
            if (($result = $renderer-&gt;render($node, $this)) !== null) {
                return $result;
            }
        }

        throw new NoMatchingRendererException('Unable to find corresponding renderer for node type ' . \get_class($node));
    }

    public function getBlockSeparator(): string
    {
        return $this-&gt;environment-&gt;getConfiguration()-&gt;get('renderer/block_separator');
    }

    public function getInnerSeparator(): string
    {
        return $this-&gt;environment-&gt;getConfiguration()-&gt;get('renderer/inner_separator');
    }
}
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