This is probably a side-effect of coming from OO land, but I'm confused about how to organize my data. Let's say I want to model musical information that occurs on a single staff. A staff consists of a list of StaffItem which occurs at specific times. type Time = Double type Staff = [(Time,StaffItem)] A StaffItem can be one of several things. Let's say it can be a "chord" or a "control". I might like to define Chord and Control first: data Chord = Chord { duration :: Double, notes :: [Note] } data Control = DynamicMark Int | TempoMark Int Okay, so now I want to express the idea a StaffItem can be a Chord or a Control. data StaffItem = StaffItemChord Chord | StaffItemControl Control My problem is the awkward need for separately named constructors "StaffItemChord" and "StaffItemControl". Is there a better way? (Is this even right?) Thanks, Mike