On Wed, 6 Mar 2002, Alan Kay wrote:

> Hannes --
> 
> At 3:25 PM +0100 3/6/02, Hannes Hirzel wrote:
> >I think I try first one of the standard Prolog text book maze
> >traversing example first (without graphics) and then try to
> >add a Morphic animation.
> 
> Sounds good. Keep us posted.
> 
> Cheers,
> 
> Alan

I'm already facing a problem I can't resolve. Although the documentation
speaks of lists

>In Prolog/V, lists have the same syntax as in standard Prolog, for
>example:
>    []    [y, #John, 'a string', #(1 2)]    [[1,2], 3 | [4,5]]

I can't  compile a clause which contains an empty list. For example

trans(X,[A|B]) :- 
      delta(X,A,Y),   
      write(X),
      write('  '),
      write([A|B]),
      nl,
      trans(Y,B).  
trans(X,[]) :- 
      final(X),
      write(X),
      write('  '),
      write([]), nl.


gives an error 'emptyList not understood' (besides that you have to write 
nl() for the new line).

This involves fixing the class #Prolog, something I don't feel comfortable
with. Does anybody have a suggestions? Bjian?


Cheers

Hannes Hirzel