Till now we have used a static variable/getter/setter to decide what type of result should be returned when a formula is evaluated and an array is the result. This is messy; it would be much better to use an instance variable instead. We cannot eliminate `setArrayReturnType` and `getArrayReturnType` because that would be a BC break. I am considering whether they should be deprecated. In the meantime, I have added a new instance property `instanceArrayReturnType` with getter and setter methods. The property is initially null, and, if it remains so when needed, the static property will be used instead. However, if it is set, its value will be used.
The CONCATENATE function has been treated as equivalent to CONCAT. This is not how it is treated in Excel; it is closer to (and probably identical to) the ampersand concatenate operator. The difference manifests itself when any of the arguments is an array (typically a cell range). Code is added to support this difference.
Support for array results is added to Csv Writer, Html Writer, and Ods Reader and Writer. I have not figured out how to get it to work with Xls.
oleibman