在Prolog中解决逻辑难题

Question

我正在学习Prolog，但我遇到了这个问题，我真的不知道如何完成它。我认为我的代码是对的，但我在 Sictus 中不断收到警告，我不知道我的错误在哪里。

问题是这样的：

/*
    File:       fall_dance_competition.pl
    Purpose:    Solve the Fall "Dance Competition" puzzle
    Notes:
    Saturday night, four couples went to the town’s annual fall dance 
    competition. Each couple dressed in matching colors and they all
    performed very well. The competition was fierce but friendly and
    everyone had a grand time. Determine the name of each couple, 
    their place in the competition, and the color each couple wore.
    1. Tom, who wasn’t married to Jean, placed better than Mary 
       and her husband but worse than the West couple did.
    2. The couple wearing brown won the event. Mr. and Mrs. 
       King came in 4th place.
    3. Bill Snow and his wife didn’t wear the green outfits. 
       Jean wasn’t married to John.
    4. The couple wearing blue placed after the couple wearing red 
       but before the King couple.
    5. From 4th place to 1st place, the couples won in the following 
       order: John and his wife, the
       couple wearing blue, Mr. and Mrs. Forest, Brenda and her husband.
    6. George and his wife placed better than Tom and Sara.
*/

这是我的代码：

use_module( library(basics)).use_module(library(lists)).
lista([pareja(_,_,_,_,_),pareja(_,_,_,_,_),
       pareja(_,_,_,_,_),pareja(_,_,_,_,_)]).
constraints( S ) :-      
    member(pareja(tom, _, _, _, _), S)
    member(pareja(_, jean, _, _, _), S)
    member(pareja(_, mary, _, _, _), S)
    member(pareja(_, _, west, _, _), S)
    perm2(Left_1, Right_1, pareja(tom, _, _, _, _), pareja(_, mary, _, _, _))
    nextto(Left_1, Right_1, S)
    perm2(Left_2, Right_2, pareja(_, _, west, _, _), pareja(tom, _, _, _, _))
    nextto(Left_2, Right_2, S)
    S = [pareja(_, _, _, 1, brown), _, _, _]
    S = [_, _, _, pareja(_, _, king, 4, _)]
    member(pareja(bill, _, snow, _, _), S)
    member(pareja(_, _, _, _, green), S)
    member(pareja(john, _, _, _, _), S)
    nextto(pareja(_, _, _, _, red), pareja(_, _, _, _, blue), S)
    nextto(pareja(_, _, _, _, blue), pareja(_, _, king, _, _), S)
    S = [_, _, _, pareja(john, _, _, 4, _)]
    S = [_, _, pareja(_, _, _, 3, blue), _]
    S = [_, pareja(_, _, forest, 2, _), _, _]
    S = [pareja(_, brenda, _, 1, _), _, _, _]   
    member(pareja(george, _, _, _, _), S)
    member(pareja(tom, sara, _, _, _), S)
    nextto(pareja(george, _, _, _, _), pareja(tom, sara, _, _, _), S).
green( Who ) :-
    lista(S),
    constraints(S),
    member(pareja(_, Who, _, _, green), S). 
nextto(X, Y, List) :- append(_, [X,Y|_], List).
append([X|Y],Z,[X|W]) :- append(Y,Z,W).  
append([],X,X).
member(X,[X|T]).
member(X,[H|T]) :- member(X,T).
perm2(X,Y, X,Y).
perm2(X,Y, Y,X).

我用了一些斑马拼图的例子来做到这一点。

Answer 1

将程序的第一行更改为：

:- use_module(library(basics)).
:- use_module(library(lists)).

检查这是否解决了问题。 use_module/1是一个指令，必须这样写。

Answer 2

您不知何故在constrains/1谓词的末尾错过了许多逗号。尝试运行文件时，这将产生很多错误。

它应该是这样的：

constraints( S ) :-      
    member(pareja(tom, _, _, _, _), S),
    member(pareja(_, jean, _, _, _), S),
    member(pareja(_, mary, _, _, _), S),
    member(pareja(_, _, west, _, _), S),
    perm2(Left_1, Right_1, pareja(tom, _, _, _, _), pareja(_, mary, _, _, _)),
    nextto(Left_1, Right_1, S),
    perm2(Left_2, Right_2, pareja(_, _, west, _, _), pareja(tom, _, _, _, _)),
    nextto(Left_2, Right_2, S),
    S = [pareja(_, _, _, 1, brown), _, _, _],
    S = [_, _, _, pareja(_, _, king, 4, _)],
    member(pareja(bill, _, snow, _, _), S),
    member(pareja(_, _, _, _, green), S),
    member(pareja(john, _, _, _, _), S),
    nextto(pareja(_, _, _, _, red), pareja(_, _, _, _, blue), S),
    nextto(pareja(_, _, _, _, blue), pareja(_, _, king, _, _), S),
    S = [_, _, _, pareja(john, _, _, 4, _)],
    S = [_, _, pareja(_, _, _, 3, blue), _],
    S = [_, pareja(_, _, forest, 2, _), _, _],
    S = [pareja(_, brenda, _, 1, _), _, _, _],  
    member(pareja(george, _, _, _, _), S),
    member(pareja(tom, sara, _, _, _), S),
    nextto(pareja(george, _, _, _, _), pareja(tom, sara, _, _, _), S).