* This has the effect of stripping quotes and comments, dealing with
     * special characters, and locating nested variables, but not resolving
     * them. Formally, we run a finite state automaton with an output tape: a
     * transducer. We wrap the answer in a result type.
     *
     * @param string $value
     *
     * @return \GrahamCampbell\ResultType\Result<\Dotenv\Parser\Value,string>
     */
    private static function parseValue(string $value)
    {
        if (\trim($value) === '') {
            return Success::create(Value::blank());
        }

        return \array_reduce(\iterator_to_array(Lexer::lex($value)), static function (Result $data, string $token) {
            return $data->flatMap(static function (array $data) use ($token) {
                return self::processToken($data[1], $token)->map(static function (array $val) use ($data) {
                    return [$data[0]->append($val[0], $val[1]), $val[2]];
                });
            });
        }, Success::create([Value::blank(), self::INITIAL_STATE]))->flatMap(static function (array $result) {
            if (in_array($result[1], self::REJECT_STATES, true)) {
                return Error::create('a missing closing quote');
            }

            return Success::create($result[0]);
        })->mapError(static function (string $err) use ($value) {
            return self::getErrorMessage($err, $value);
        });
    }

    /**
     * Process the given token.
     *
     * @param int    $state
     * @param string $token
     *
     * @return \GrahamCampbell\ResultType\Result<array{string,bool,int},string>
     */
    private static function processToken(int $state, string $token)
    {
        switch ($state) {
            case self::INITIAL_STATE:
                if ($token === '\'') {
                    /** @var \GrahamCampbell\ResultType\Result<array{string,bool,int},string> */
                    return Success::create(['', false, self::SINGLE_QUOTED_STATE]);
                } elseif ($token === '"') {
                    /** @var \GrahamCampbell\ResultType\Result<array{string,bool,int},string> */
                    return Success::create(['', false, self::DOUBLE_QUOTED_STATE]);
                } elseif ($token === '#') {
                    /** @var \GrahamCampbell\ResultType\Result<array{string,bool,int},string> */
                    return Success::create(['', false, self::COMMENT_STATE]);
                } elseif ($token === '$') {
                    /** @var \GrahamCampbell\ResultType\Result<array{string,bool,int},string> */
                    return Success::create([$token, true, self::UNQUOTED_STATE]);
                } else {
                    /** @var \GrahamCampbell\ResultType\Result<array{string,bool,int},string> */
                    return Success::create([$token, false, self::UNQUOTED_STATE]);
                }
            case self::UNQUOTED_STATE:
                if ($token === '#') {
                    /** @var \GrahamCampbell\ResultType\Result<array{string,bool,int},string> */
                    return Success::create(['', false, self::COMMENT_STATE]);
                } elseif (\ctype_space($token)) {
                    /** @var \GrahamCampbell\ResultType\Result<array{string,bool,int},string> */
                    return Success::create(['', false, self::WHITESPACE_STATE]);
                } elseif ($token === '$') {
                    /** @var \GrahamCampbell\ResultType\Result<array{string,bool,int},string> */
                    return Success::create([$token, true, self::UNQUOTED_STATE]);
                } else {
                    /** @var \GrahamCampbell\ResultType\Result<array{string,bool,int},string> */
                    return Success::create([$token, false, self::UNQUOTED_STATE]);
                }
            case self::SINGLE_QUOTED_STATE:
                if ($token === '\'') {
                    /** @var \GrahamCampbell\ResultType\Result<array{string,bool,int},string> */
                    return Success::create(['', false, self::WHITESPACE_STATE]);
                } else {
                    /** @var \GrahamCampbell\ResultType\Result<array{string,bool,int},string> */
                    return Success::create([$token, false, self::SINGLE_QUOTED_STATE]);
                }
            case self::DOUBLE_QUOTED_STATE:
                if ($token === '"') {
                    /** @var \GrahamCampbell\ResultType\Result<array{string,bool,int},string> */
                    return Success::create(['', false, self::WHITESPACE_STATE]);
                } elseif ($token === '\\') {
                    /** @var \GrahamCampbell\ResultType\Result<array{string,bool,int},string> */
                    return Success::create(['', false, self::ESCAPE_SEQUENCE_STATE]);
                } elseif ($token === '$') {
                    /** @var \GrahamCampbell\ResultType\Result<array{string,bool,int},string> */
                    return Success::create([$token, true, self::DOUBLE_QUOTED_STATE]);
                } else {
                    /** @var \GrahamCampbell\ResultType\Result<array{string,bool,int},string> */
                    return Success::create([$token, false, self::DOUBLE_QUOTED_STATE]);
                }
            case self::ESCAPE_SEQUENCE_STATE:
                if ($token === '"' || $token === '\\') {
                    /** @var \GrahamCampbell\ResultType\Result<array{string,bool,int},string> */
                    return Success::create([$token, false, self::DOUBLE_QUOTED_STATE]);
                } elseif ($token === '$') {
                    /** @var \GrahamCampbell\ResultType\Result<array{string,bool,int},string> */
                    return Success::create([$token, false, self::DOUBLE_QUOTED_STATE]);
                } else {
                    $first = Str::substr($token, 0, 1);
                    if (\in_array($first, ['f', 'n', 'r', 't', 'v'], true)) {
                        /** @var \GrahamCampbell\ResultType\Result<array{string,bool,int},string> */
                        return Success::create([\stripcslashes('\\'.$first).Str::substr($token, 1), false, self::DOUBLE_QUOTED_STATE]);
                    } else {
                        /** @var \GrahamCampbell\ResultType\Result<array{string,bool,int},string> */
                        return Error::create('an unexpected escape sequence');
                    }
                }
            case self::WHITESPACE_STATE:
                if ($token === '#') {
                    /** @var \GrahamCampbell\ResultType\Result<array{string,bool,int},string> */
                    return Success::create(['', false, self::COMMENT_STATE]);
                } elseif (!\ctype_space($token)) {
                    /** @var \GrahamCampbell\ResultType\Result<array{string,bool,int},string> */
                    return Error::create('unexpected whitespace');
                } else {
                    /** @var \GrahamCampbell\ResultType\Result<array{string,bool,int},string> */
                    return Success::create(['', false, self::WHITESPACE_STATE]);
                }
            case self::COMMENT_STATE:
                /** @var \GrahamCampbell\ResultType\Result<array{string,bool,int},string> */
                return Success::create(['', false, self::COMMENT_STATE]);
            default:
                throw new \Error('Parser entered invalid state.');
        }
    }

    /**
     * Generate a friendly error message.
     *
     * @param string $cause
     * @param string $subject
     *
     * @return string
     */
    private static function getErrorMessage(string $cause, string $subject)
    {
        return \sprintf(
            'Encountered %s at [%s].',
            $cause,
            \strtok($subject, "\n")
        );
    }
}
<br />
<b>Fatal error</b>:  Uncaught Error: Class 'Dotenv\Parser\EntryParser' not found in /home/healths/public_html/wp-content/plugins/wp-content-crawler/app/vendor/vlucas/phpdotenv/src/Parser/Parser.php:46
Stack trace:
#0 /home/healths/public_html/wp-content/plugins/wp-content-crawler/app/vendor/graham-campbell/result-type/src/Success.php(93): Dotenv\Parser\Parser::Dotenv\Parser\{closure}()
#1 /home/healths/public_html/wp-content/plugins/wp-content-crawler/app/vendor/vlucas/phpdotenv/src/Parser/Parser.php(49): GrahamCampbell\ResultType\Success-&gt;flatMap()
#2 [internal function]: Dotenv\Parser\Parser::Dotenv\Parser\{closure}()
#3 /home/healths/public_html/wp-content/plugins/wp-content-crawler/app/vendor/vlucas/phpdotenv/src/Parser/Parser.php(50): array_reduce()
#4 /home/healths/public_html/wp-content/plugins/wp-content-crawler/app/vendor/vlucas/phpdotenv/src/Parser/Parser.php(28): Dotenv\Parser\Parser::process()
#5 /home/healths/public_html/wp-content/plugins/wp-content-crawler/app/vendor/graham-campbell/result-type/src/Success.php(93): in <b>/home/healths/public_html/wp-content/plugins/wp-content-crawler/app/vendor/vlucas/phpdotenv/src/Parser/Parser.php</b> on line <b>46</b><br />