/* 

  zebra benchmark in Picat v3.

  bench/zebra.pl
  https://github.com/SWI-Prolog/bench

  Changes:
  - $ escaped occurrences of house/5 in top/0.
  - added output
  - commented definition of member/3

  This Picat model was created by Hakan Kjellerstrand, hakank@gmail.com
  See also my Picat page: http://www.hakank.org/picat/

*/

main => go.


go ?=>
  houses(Houses),
  member($house(red, english, _, _, _), Houses),
  member($house(_, spanish, dog, _, _), Houses),
  member($house(green, _, _, coffee, _), Houses),
  member($house(_, ukrainian, _, tea, _), Houses),
  right_of($house(green,_,_,_,_), $house(ivory,_,_,_,_), Houses),
  member($house(_, _, snails, _, winstons), Houses),
  member($house(yellow, _, _, _, kools), Houses),
  Houses = $[_, _, house(_, _, _, milk, _), _,_],
  Houses = $[house(_, norwegian, _, _, _)|_],
  next_to($house(_,_,_,_,chesterfields), $house(_,_,fox,_,_), Houses),
  next_to($house(_,_,_,_,kools), $house(_,_,horse,_,_), Houses),
  member($house(_, _, _, orange_juice, lucky_strikes), Houses),
  member($house(_, japanese, _, _, parliaments), Houses),
  next_to($house(_,norwegian,_,_,_), $house(blue,_,_,_,_), Houses),
  member($house(_, _, zebra, _, _), Houses),
  member($house(_, _, _, water, _), Houses),
  print_houses(Houses),
  fail,

  nl.

go => true.

% """
% Where does the zebra live?
% Puzzle solution written by Claude Sammut.
% """
top:-
	houses(Houses),
	member($house(red, english, _, _, _), Houses),
	member($house(_, spanish, dog, _, _), Houses),
	member($house(green, _, _, coffee, _), Houses),
	member($house(_, ukrainian, _, tea, _), Houses),
	right_of($house(green,_,_,_,_), $house(ivory,_,_,_,_), Houses),
	member($house(_, _, snails, _, winstons), Houses),
	member($house(yellow, _, _, _, kools), Houses),
	Houses = $[_, _, house(_, _, _, milk, _), _,_],
	Houses = $[house(_, norwegian, _, _, _)|_],
	next_to($house(_,_,_,_,chesterfields), $house(_,_,fox,_,_), Houses),
	next_to($house(_,_,_,_,kools), $house(_,_,horse,_,_), Houses),
	member($house(_, _, _, orange_juice, lucky_strikes), Houses),
	member($house(_, japanese, _, _, parliaments), Houses),
	next_to($house(_,norwegian,_,_,_), $house(blue,_,_,_,_), Houses),
	member($house(_, _, zebra, _, _), Houses),
	member($house(_, _, _, water, _), Houses).

houses([
	house(_, _, _, _, _),
	house(_, _, _, _, _),
	house(_, _, _, _, _),
	house(_, _, _, _, _),
	house(_, _, _, _, _)
]).

right_of(A, B, [B, A | _]).
right_of(A, B, [_ | Y]) :- right_of(A, B, Y).

next_to(A, B, [A, B | _]).
next_to(A, B, [B, A | _]).
next_to(A, B, [_ | Y]) :- next_to(A, B, Y).

% member(X, [X|_]).
% member(X, [_|Y]) :- member(X, Y).

print_houses([A|B]) :- !,
	write(A), nl,
	print_houses(B).
print_houses([]).