If you have nested type, then it usually makes sense to have Show defined
for the inside types, too, but it's not a requirement. Technically, only
when you call 'show' for something in the data type you are defining Show
for, *then* you need a Show instance defined for that inside-type.
On Fri, May 20, 2011 at 12:15 AM, Andrew Coppin wrote: On 19/05/2011 10:11 PM, Artyom Kazak wrote: And I can declare an instance for (x, y) which does NOT implies (Show x): instance Show (x, y) where
show _ = "I'm tuple! Hooray!" Ah. So it's a feature. Fortunately I refactored the program where this came up, so it's no longer
an issue. I just wanted to see whether or not it was a bug. PS. Wouldn't such an instance require FlexibleContexts or something? _______________________________________________
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe --
Markus Läll