Am Montag, 21. November 2005 14:27 schrieb David Roundy: > On Sun, Nov 20, 2005 at 04:21:05PM +0100, Wolfgang Jeltsch wrote: > > Am Samstag, 19. November 2005 17:35 schrieb Bulat Ziganshin: > > > 7. OOP-like fields inheritance: > > > > > > data Coord = { x,y :: Double } > > > data Point : Coord = { c :: Color } > > > > > > of course this is just another sort of syntax sugar once we start > > > using classes to define getter/setter functions > > > > I thought that even many OO people say that inheritance of fields is not > > good practice. So why should we want to support it? > > Think of it instead as being syntactic sugar for a class declaration: > > class Coord a where > get_x :: a -> Double > get_y :: a -> Double > set_x :: Double -> a -> a > set_y :: Double -> a -> a
As I pointed out in another e-mail just sent, this kind of special syntax only solves a very specific problem so that it's questionable whether this syntax should be included into Haskell. However, if we manage to create a more generalized approach, inclusion of it into the language might be quite fine. In addition, having a line which begins with "data" declaring a class is *very* misleading, in my opinion. > [...] Best wishes, Wolfgang _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe