Rubberduck.Parsing.Preprocessing.ConcatExpression.Evaluate C# (CSharp) Method

        public override IValue Evaluate()
        {
            var left = _left.Evaluate();
            var right = _right.Evaluate();
            if (left == null && right == null)
            {
                return null;
            }
            string leftValue = string.Empty;
            if (left != null)
            {
                leftValue = left.AsString;
            }
            string rightValue = string.Empty;
            if (right != null)
            {
                rightValue = right.AsString;
            }
            return new StringValue(leftValue + rightValue);
        }
    }