> Regarding the type field, look for "enum EventType type;" in the article. OK. If I understand correctly, you want to use that field in other contexts than do

> Regarding the type field, look for "enum EventType type;" in the article. OK. If I understand correctly, you want to use that field in other contexts than doing a switch on it, whereas in Haskell the usual way of consuming the type tag is to do such a switch, as in the article's example: case event of ClickEvent x y -> <do click stuff> PaintEvent color -> <do paint stuff> // there are no other possible cases, so no default case needed > For example, I could separate a large array of sum-type data into separate arrays, and also process them separately. Sure, but you can do that with a case expression as above. Here is a complete example: data Event = ClickEvent Int Int | PaintEvent Int -- separate a list of Events into two lists, the first holding the payloads -- of the click events, the other the payloads of the paint events separate :: [Event] -> ([(Int, Int)], [Int]) separate [] = ([], []) separate (event : events) = case event of ClickEvent x y -> ((x, y) : clicks, colors) PaintEvent color -> (clicks, color : colors) where (clicks, colors) = separate events example = [ClickEvent 1 2, PaintEvent 42, ClickEvent 3 4, PaintEvent 23] Running it: > separate example ([(1,2),(3,4)],[42,23]) You can now go ahead and process the list [(1,2),(3,4)] separately from [42,23]. (Depending on the exact specification and performance requirements, the code might be written a bit differently in the real world.) EDIT: Ah, you edited your post while I was writing. Oh well. Regarding reifying constructors as integers or whatever, yes, you might have to write a two-line function to do that.