compiler-errors - 为什么此prolog程序无法编译？

Question

我有一个序言程序。这些行阻止其编译:

wins(A,B,C,D) :- convert(A,W), value(W,P), convert(B,X), value(X,Q), 
convert(C, Y), value(Y,R), convert(D,Z), value(Z,S), card(A), card(B), card(C), card(D),
(P+Q)>(R+S), (P+Q)<22, A/=B, A/=C, A/=D, B/=C, B/=D, C/=D. %this is not compiling

wins(A,B,C,D) :- convert(A,W), value(W,P), convert(B,X), value(X,Q), 
convert(C,Y), value(Y,R), convert(D,Z), value(Z,S), card(A), card(B), card(C), card(D),
(R+S)>21, (P+Q)<22, A/=B, A/=C, A/=D, B/=C, B/=D, C/=D. %this is not compiling

我收到以下错误:

| ?- [blackjack].
compiling /home/ross/flash/current/CS390/blackjack.pl for byte code...
/home/ross/flash/current/CS390/blackjack.pl:47:25: syntax error: . or operator expected after expression
/home/ross/flash/current/CS390/blackjack.pl:51:22: syntax error: . or operator expected after expression
2 error(s)
compilation failed

Answer 1

/=不是有效的运算符。您一定是\=的意思。

(更好的是，如果您的Prolog支持dif(A,B)，则将dif调用放在该子句的其余部分之前。)