CODEWITHSUNDEEP
answer-set-programmingclingo
OzanCinci
OzanCinci

Reputation: 13

Clingo and or logical syntax error: unexpected !=

I develop an application in clingo and here is my code:

conflicting_hours(Course1, Section1, Room, Start1, Hour1) :-
    occupies(Course1, Section1, Room, Start1, Hour1),
    occupies(Course2, Section2, Room, Start2, Hour2),
    different_course(Course1,Course2,Section1,Section2),
    check_hour_intersection(Start1,Start2,Hour1) ; check_hour_intersection(Start2,Start1,Hour2).

different_course(N1,N2,S1,S2) :-
    course(N1,S1,_,_,_,_,_,_),
    course(N2,S2,_,_,_,_,_,_),
    (N1!=N2 ; S1!=S2).

and here is error:

soln.lp:62:8-10: error: syntax error, unexpected !=, expecting )

*** ERROR: (clingo): parsing failed

It gives this error when I try to put braces around (N1!=N2 ; S1!=S2). When I remove brackets it woks well but logic is wrong. Why it is invalid syntax.

Upvotes: 0

Views: 132

Answers (1)

Paulo Moura
Paulo Moura

Reputation: 18663

Try:

different_course(N1,N2,S1,S2) :-
    course(N1,S1,_,_,_,_,_,_),
    course(N2,S2,_,_,_,_,_,_),
    ((N1 != N2) ; (S1 != S2)).

Also, in the first clause, should it be instead:

conflicting_hours(Course1, Section1, Room, Start1, Hour1) :-
    occupies(Course1, Section1, Room, Start1, Hour1),
    occupies(Course2, Section2, Room, Start2, Hour2),
    different_course(Course1,Course2,Section1,Section2),
    (   check_hour_intersection(Start1,Start2,Hour1)
    ;   check_hour_intersection(Start2,Start1,Hour2)
    ).

Upvotes: 0

Related Questions