succ Blue cannot return MrX unless Blue and MrX have the same type. What I meant was that you would say: 'succ (Detective Red)' ==> Detective Green 'succ (Detective Green)' ==> Detective Blue 'succ (Detective Blue)' ==> Fugitive MrX -- Hal Daume III "Computer science is no more about computers | hdaume@isi.edu than astronomy is about telescopes." -Dijkstra | www.isi.edu/~hdaume On Thu, 20 Feb 2003, Mike T. Machenry wrote:
I tried this. It doesn't work. succ Blue is an exception. Anybody else know how this should be done?
Thanks, -mike
On Thu, Feb 20, 2003 at 08:00:04AM -0800, Hal Daume III wrote:
Question 1: Is there an easier, more elegant way to write this code?
For the most part, no.
Question 2: Is there a way to express the following relationship? I want to have a set of symbols with ordering and another set that is part of that ordering but with a different parent. For exammple,
data Player = Detective | Fugitive deriving (Enum) data Detective = Red | Green | Blue deriving (Enum) data Fugitive = MrX deriving (Enum)
How about something like:
data Player = Detective Detective | Fugitive Fugitive deriving (Enum) data Detective = Red | Green | Blue deriving (Enum) data Fugitive = MrX deriving (Enum)
(I'm not sure if the deriving Enum on Player will be exactly what you want -- I think so though. I don't derive this class very often.)
Then you can test detectiveness by:
isDetective (Detective _) = True isDetective _ = False
HTH
- Hal
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