[Haskell-cafe] Problem with question 3 about knights and knaves on wikipedia

[Dan Piponi]

On 8/9/07, Peter Verswyvelen <bf3 at telenet.be> wrote:
> I was writing some haskell code for fun to solve some "knights and knaves"
>              .      .     .
>         John: answers either Yes or No, and you can now solve the problem.

We can write a Haskell *program* to solve this problem. But is there a
nice way to make the Haskell *compiler* itself solve this problem? In
particular, can we write equations for the values of john and bill and
somehow have the type inferencer figure out whether the Haskell types
of john and bill are Knight or Knave?
--
Dan