what mistake in this medical diagnosis prolog?

Question

i am still new about prolog, i have a problem about a simple medical diagnosis program using a prolog, i try to find code about this medical diagnosis system to make it work, but i cant, i dont know what i need to change, i use SWI prolog software.

here the prolog code that i try use it show error in domains, show "syntax error= operator expected"

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.

what i can do to make it working?

Answer 1

As explained in the comments, the code was likely written for a logic programming language that shares features with Prolog but that's not considered a Prolog system (w.r.t to both official and de facto Prolog standards).

A quick rewrite of the code to get it running on SWI-Prolog is:

go :-
    write('What is the patient''s name? '),
    read(Patient),
    hypothesis(Patient,Disease),
    write_list([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_list(['Does ',Patient,' have a fever (y/n) ?']),
    response(Reply),
    Reply='y'.

symptom(Patient,rash) :-
    write_list(['Does ',Patient,' have a rash (y/n) ?']),
    response(Reply),
    Reply='y'.

symptom(Patient,headache) :-
    write_list(['Does ',Patient,' have a headache (y/n) ?']),
    response(Reply),
    Reply='y'.

symptom(Patient,runny_nose) :-
    write_list(['Does ',Patient,' have a runny_nose (y/n) ?']),
    response(Reply),
    Reply='y'.

symptom(Patient,conjunctivitis) :-
    write_list(['Does ',Patient,' have a conjunctivitis (y/n) ?']),
    response(Reply),
    Reply='y'.

symptom(Patient,cough) :-
    write_list(['Does ',Patient,' have a cough (y/n) ?']),
    response(Reply),
    Reply='y'.

symptom(Patient,body_ache) :-
    write_list(['Does ',Patient,' have a body_ache (y/n) ?']),
    response(Reply),
    Reply='y'.

symptom(Patient,chills) :-
    write_list(['Does ',Patient,' have a chills (y/n) ?']),
    response(Reply),
    Reply='y'.

symptom(Patient,sore_throat) :-
    write_list(['Does ',Patient,' have a sore_throat (y/n) ?']),
    response(Reply),
    Reply='y'.

symptom(Patient,sneezing) :-
    write_list(['Does ',Patient,' have a sneezing (y/n) ?']),
    response(Reply),
    Reply='y'.

symptom(Patient,swollen_glands) :-
    write_list(['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).

write_list([]).
write_list([Term| Terms]) :-
    write(Term),
    write_list(Terms).

response(Reply) :-
    get_single_char(Code),
    put_code(Code), nl,
    char_code(Reply, Code).

for convenience, this rewrite makes use of SWI-Prolog specific built-in predicate, get_single_char/1. You will need to replace its call if you want to adapt the code to run on other Prolog systems.