There were something like 8 research groups involved in inventing the language, and at each group there had been previous proto-Haskell languages in house. As a

There were something like 8 research groups involved in inventing the language, and at each group there had been previous proto-Haskell languages in house. As a result there were different styles that emerged. By the mid-2000s though, there's a fairly universal style based on Glasgow, IMO.