我正在为大学建设一些东西，我收到以下错误： 错误：[Thread pce] path / diagnosis.pl:6：3：语法错误：操作员期望 我看了第6行，但我不知道出了什么问题。我尝试删除空格，更改变量名称，重新定义，没有任何作用。 这是一张图片： enter image description here 这是代码：
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domains
Disease,indication = symbol
Patient,name = string
predicates
hypothesis(string,disease)
symptom(name,indication)
response(char)
go
clauses
go :-
write("What is the patient's name? "),
readln(Patient),
hypothesis(Patient,Disease),
write(Patient,"probably has ",Disease,"."),nl.
go :-
write("Sorry, I don't seem to be able to"),nl,
write("diagnose the disease."),nl.
symptom(Patient,fever) :-
write("Does ",Patient," have a fever (y/n) ?"),
response(Reply),
Reply='y'.
symptom(Patient,rash) :-
write("Does ",Patient," have a rash (y/n) ?"),
response(Reply),
Reply='y'.
symptom(Patient,headache) :-
write("Does ",Patient," have a headache (y/n) ?"),
response(Reply),
Reply='y'.
symptom(Patient,runny_nose) :-
write("Does ",Patient," have a runny_nose (y/n) ?"),
response(Reply),
Reply='y'.
symptom(Patient,conjunctivitis) :-
write("Does ",Patient," have a conjunctivitis (y/n) ?"),
response(Reply),
Reply='y'.
symptom(Patient,cough) :-
write("Does ",Patient," have a cough (y/n) ?"),
response(Reply),
Reply='y'.
symptom(Patient,body_ache) :-
write("Does ",Patient," have a body_ache (y/n) ?"),
response(Reply),
Reply='y'.
symptom(Patient,chills) :-
write("Does ",Patient," have a chills (y/n) ?"),
response(Reply),
Reply='y'.
symptom(Patient,sore_throat) :-
write("Does ",Patient," have a sore_throat (y/n) ?"),
response(Reply),
Reply='y'.
symptom(Patient,sneezing) :-
write("Does ",Patient," have a sneezing (y/n) ?"),
response(Reply),
Reply='y'.
symptom(Patient,swollen_glands) :-
write("Does ",Patient," have a swollen_glands (y/n) ?"),
response(Reply),
Reply='y'.
hypothesis(Patient,measles) :-
symptom(Patient,fever),
symptom(Patient,cough),
symptom(Patient,conjunctivitis),
symptom(Patient,runny_nose),
symptom(Patient,rash).
hypothesis(Patient,german_measles) :-
symptom(Patient,fever),
symptom(Patient,headache),
symptom(Patient,runny_nose),
symptom(Patient,rash).
hypothesis(Patient,flu) :-
symptom(Patient,fever),
symptom(Patient,headache),
symptom(Patient,body_ache),
symptom(Patient,conjunctivitis),
symptom(Patient,chills),
symptom(Patient,sore_throat),
symptom(Patient,runny_nose),
symptom(Patient,cough).
hypothesis(Patient,common_cold) :-
symptom(Patient,headache),
symptom(Patient,sneezing),
symptom(Patient,sore_throat),
symptom(Patient,runny_nose),
symptom(Patient,chills).
hypothesis(Patient,mumps) :-
symptom(Patient,fever),
symptom(Patient,swollen_glands).
hypothesis(Patient,chicken_pox) :-
symptom(Patient,fever),
symptom(Patient,chills),
symptom(Patient,body_ache),
symptom(Patient,rash).
hypothesis(Patient,measles) :-
symptom(Patient,cough),
symptom(Patient,sneezing),
symptom(Patient,runny_nose).
response(Reply) :-
readchar(Reply),
write(Reply),nl.