public TextExpressionNode(int index, int length, string text, TextExpression expression)
		{
			_text = text;
			_index = Math.Max(index, -1);
			_length = Math.Max(length, 0);
			_expression = expression;
		}
 public TextExpressionNode(int index, int length, string text, TextExpression expression)
 {
     _text       = text;
     _index      = Math.Max(index, -1);
     _length     = Math.Max(length, 0);
     _expression = expression;
 }