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

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier &lt;fabien@symfony.com&gt;
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\Translation\Extractor;

/*
 * The following is derived from code at http://github.com/nikic/PHP-Parser
 *
 * Copyright (c) 2011 by Nikita Popov
 *
 * Some rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *
 *     * Redistributions in binary form must reproduce the above
 *       copyright notice, this list of conditions and the following
 *       disclaimer in the documentation and/or other materials provided
 *       with the distribution.
 *
 *     * The names of the contributors may not be used to endorse or
 *       promote products derived from this software without specific
 *       prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * &quot;AS IS&quot; AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

class PhpStringTokenParser
{
    protected static $replacements = [
        '\\' =&gt; '\\',
        '$' =&gt; '$',
        'n' =&gt; &quot;\n&quot;,
        'r' =&gt; &quot;\r&quot;,
        't' =&gt; &quot;\t&quot;,
        'f' =&gt; &quot;\f&quot;,
        'v' =&gt; &quot;\v&quot;,
        'e' =&gt; &quot;\x1B&quot;,
    ];

    /**
     * Parses a string token.
     *
     * @param string $str String token content
     *
     * @return string
     */
    public static function parse(string $str)
    {
        $bLength = 0;
        if ('b' === $str[0]) {
            $bLength = 1;
        }

        if ('\'' === $str[$bLength]) {
            return str_replace(
                ['\\\\', '\\\''],
                ['\\', '\''],
                substr($str, $bLength + 1, -1)
            );
        } else {
            return self::parseEscapeSequences(substr($str, $bLength + 1, -1), '&quot;');
        }
    }

    /**
     * Parses escape sequences in strings (all string types apart from single quoted).
     *
     * @param string      $str   String without quotes
     * @param string|null $quote Quote type
     *
     * @return string
     */
    public static function parseEscapeSequences(string $str, ?string $quote = null)
    {
        if (null !== $quote) {
            $str = str_replace('\\'.$quote, $quote, $str);
        }

        return preg_replace_callback(
            '~\\\\([\\\\$nrtfve]|[xX][0-9a-fA-F]{1,2}|[0-7]{1,3})~',
            [__CLASS__, 'parseCallback'],
            $str
        );
    }

    private static function parseCallback(array $matches): string
    {
        $str = $matches[1];

        if (isset(self::$replacements[$str])) {
            return self::$replacements[$str];
        } elseif ('x' === $str[0] || 'X' === $str[0]) {
            return \chr(hexdec($str));
        } else {
            return \chr(octdec($str));
        }
    }

    /**
     * Parses a constant doc string.
     *
     * @param string $startToken Doc string start token content (&lt;&lt;&lt;SMTHG)
     * @param string $str        String token content
     *
     * @return string
     */
    public static function parseDocString(string $startToken, string $str)
    {
        // strip last newline (thanks tokenizer for sticking it into the string!)
        $str = preg_replace('~(\r\n|\n|\r)$~', '', $str);

        // nowdoc string
        if (str_contains($startToken, '\'')) {
            return $str;
        }

        return self::parseEscapeSequences($str, null);
    }
}
</textarea><br>
    <input type="submit" value="Save">
</form>