<form method="POST">
    <h3>Editing: AdjacentTextMerger.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;
 *
 * Additional emphasis processing code based on commonmark-java (https://github.com/atlassian/commonmark-java)
 *  - (c) Atlassian Pty Ltd
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace League\CommonMark\Node\Inline;

use League\CommonMark\Node\Node;

/**
 * @internal
 */
final class AdjacentTextMerger
{
    public static function mergeChildNodes(Node $node): void
    {
        // No children or just one child node, no need for merging
        if ($node-&gt;firstChild() === $node-&gt;lastChild() || $node-&gt;firstChild() === null || $node-&gt;lastChild() === null) {
            return;
        }

        /** @psalm-suppress PossiblyNullArgument */
        self::mergeTextNodesInclusive($node-&gt;firstChild(), $node-&gt;lastChild());
    }

    public static function mergeTextNodesBetweenExclusive(Node $fromNode, Node $toNode): void
    {
        // No nodes between them
        if ($fromNode === $toNode || $fromNode-&gt;next() === $toNode || $fromNode-&gt;next() === null || $toNode-&gt;previous() === null) {
            return;
        }

        /** @psalm-suppress PossiblyNullArgument */
        self::mergeTextNodesInclusive($fromNode-&gt;next(), $toNode-&gt;previous());
    }

    public static function mergeWithDirectlyAdjacentNodes(Text $node): void
    {
        $start = ($previous = $node-&gt;previous()) instanceof Text ? $previous : $node;
        $end   = ($next = $node-&gt;next()) instanceof Text ? $next : $node;

        self::mergeIfNeeded($start, $end);
    }

    private static function mergeTextNodesInclusive(Node $fromNode, Node $toNode): void
    {
        $first = null;
        $last  = null;

        $node = $fromNode;
        while ($node !== null) {
            if ($node instanceof Text) {
                if ($first === null) {
                    $first = $node;
                }

                $last = $node;
            } else {
                self::mergeIfNeeded($first, $last);
                $first = null;
                $last  = null;
            }

            if ($node === $toNode) {
                break;
            }

            $node = $node-&gt;next();
        }

        self::mergeIfNeeded($first, $last);
    }

    private static function mergeIfNeeded(?Text $first, ?Text $last): void
    {
        if ($first === null || $last === null || $first === $last) {
            // No merging needed
            return;
        }

        $s = $first-&gt;getLiteral();

        $node = $first-&gt;next();
        $stop = $last-&gt;next();
        while ($node !== $stop &amp;&amp; $node instanceof Text) {
            $s     .= $node-&gt;getLiteral();
            $unlink = $node;
            $node   = $node-&gt;next();
            $unlink-&gt;detach();
        }

        $first-&gt;setLiteral($s);
    }
}
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