Yeah, I found the ADT.Struct type with Gnol and Drow.  However, the documentation on the website gave me trouble.  I couldn't find an index to the left, just the modules themselves, so when I clicked on ADT, I couldn't see all the methods and click on them individually, I had to click on links at the top for next method, and so on until I found what I needed.

I should also have thought of concatenating strings for the field width.