Simon Marlow wrote (snipped):
I agree it's not worth arguing, it's more important to decide whether we can implement Read Version.
Why is the Read instance for Version so important? I don't really see one using it much. The only occasion I can imagine when you would actually want to create a Version value for GHC is when you send a new release out the door. I don't really the instance of Ord being that important either. What one wants to know is whether (1) version X was released later than some given date; (2) version X is lexicographically subsequent to [sequence of integers] (so GHC 6.02.1 comes after GHC 4.08.1); (3) version X is a subversion of [sequence of integers], as 6.2.1 is a subversion of 6.2; (4) version X has a tag attached meaning "DANGER. Do not use unless your name is Simon". Some way of converting a Version value to a short form (as in "GHC 6.02.1 (simony,hacked_for_windows) 13th April 2004") might be useful. For example you could do that with a date-like format string. Also you need some way Haskell can write a Version to a file so that it can be read again. But I think it's much more important to approach this from the angle of how people will actually want to use Version, instead of asking "How will we fit this into the standard Haskell classes?"