[Haskell-cafe] The Riddle of the Buddhist Monk

[Paul Johnson]

On 20/12/11 10:16, Patrick Browne wrote:
> Hi,
> I am trying to implement a set of 4 modules that blend the action of a 
> monk moving up a mountain on day 1 and returning down by the same path 
> on day 2 [1][2]. The code should reflect the fact that there is some 
> time and place which is common to the two days where the monk would 
> *meets himself*.
> My Haskell code is based on a Maude version[3][4]. Only 3 times and 
> places are considered in the code; start, meet, and end called 1,2, 
> and 3 (e.g. the start time for the upward journey is timeu1).
> Using qualified elements, I can get the meets function to give the 
> correct results, but I cannot get the location function to work.
> Is it possible the get  meets to work without qualification? Any 
> suggestions in getting  location to work?
>
> Regards,
> Pat

I think you need to rethink the solution: Haskell is not a logic 
programming language.

You definitely don't need the type class, and you don't need instances.

Paul.