uses member_/2 (the invers aregs)

% assume member_/2 is defined

solve(Neighborhood) :-

  /*
  the solution consists of five compounds
  each compound consists of the six traits of a house, in order

  position    = 1, 2, 3, 4, 5
  nationality = brit, dane, german, norwegian, swede
  colors      = blue, green, red, white, yellow
  beverages   = beer, coffee, milk, tea, water
  smokes      = bluemaster, dunhill, pallmall, prince, blend
  keeps       = cat, bird, dog, fish, horse
  */

  % the neighborhood looks like this
  Neighborhood = [
    (1,_,_,_,_,_),
    (2,_,_,_,_,_),
    (3,_,_,_,_,_),
    (4,_,_,_,_,_),
    (5,_,_,_,_,_)],

 maplist(lists:member_(Neighborhood),[
  % 1.  The Brit lives in a red house.
   (_,brit,red,_,_,_),

  % 2.  The Swede keeps dogs as pets.
   (_,swede,_,_,_,dog),

  % 3.  The Dane drinks tea.
   (_,dane,_,tea,_,_),

  % 4.  The green house is on the left of the white house (next to it).
   (A,_,green,_,_), B is A+1,
   (B,_,white,_,_),

  % 5.  The green house owner drinks coffee.
   (_,_,green,coffee,_,_),

  % 6.  The person who smokes Pall Mall rears birds.
   (_,_,_,_,pallmall,birds),

  % 7.  The owner of the yellow house smokes Dunhill.
   (_,_,yellow,_,dunhill,_),

  % 8.  The man living in the house right in the center drinks milk.
   (3,_,_,milk,_,_),

  % 9.  The Norwegian lives in the first house.
   (1,norwegian,_,_,_,_),

  % 10. The man who smokes blend lives next to the one who keeps cats.
   (C,_,_,_,blend,_), plus_or_minus_one(C, D),
   (D,_,_,_,_,cats),

  % 11. The man who keeps horses lives next to the man who smokes Dunhill.
   (E,_,_,_,_,horses), plus_or_minus_one(E, F),
   (F,_,_,_,dunhill,_),

  % 12. The owner who smokes Blue Master drinks beer.
   (_,_,_,beer,bluemaster,_),

  % 13. The German smokes Prince.
   (_,german,_,_,prince,_),

  % 14. The Norwegian lives next to the blue house.
   (G,norwegian,_,_,_,_), plus_or_minus_one(G, H),
   (H,_,blue,_,_,_),

  % 15. The man who smokes blend has a neighbor who drinks water.
   (I,_,_,_,blend,_), plus_or_minus_one(I, J),
   (J,_,_,water,_,_),

  % Question: Who owns the fish?
   (_,_,_,_,_,fish)]).

% This is probably very very very bad practice
plus_or_minus_one(I, J) :- Im is I-1, Ip is I+1, member(J, [Im, Ip]).

main :- solve(Neighborhood), maplist(writeln, Neighborhood).