Our users would really like to be able to derive new data items in WRS. Consider, a categorical item with 5,000 unique values. We can predefine several groupers in the Information Map but we will never cover all the possible combinations that users might want. If there was a CASE statement or some way of writing expressions, WRS would cover a lot more ground.
One answer is to use EG rather than WRS but we're really keen on the web tool rather than the desktop tool. WRS is much easier to use for the bulk of our user community.
You might be able to accomplish this using a SAS Stored Process and utilizing within the Information Map. The SAS Stored Process could define a custom format that the Information Map will then utilize, or some case logic to set within the initial query.
I don't believe there is a way to complete this within the Web Report Studio technology without incorporating some SAS coding skills.