Flow\JSONPath\JSONPathLexer::__construct PHP Метод

    public function __construct($expression)
    {
        $expression = trim($expression);
        if (!strlen($expression)) {
            return;
        }
        if ($expression[0] === '$') {
            $expression = substr($expression, 1);
        }
        if ($expression[0] !== '.' && $expression[0] !== '[') {
            $expression = '.' . $expression;
        }
        $this->expression = $expression;
        $this->expressionLength = strlen($expression);
    }