%% Sam's likes and dislikes in food
%% 
%% Considering the following will give some practice
%% in thinking about backtracking.
%% ?- likes(sam,dahl).
%% ?- likes(sam,chop_suey).
%% ?- likes(sam,pizza).
%% ?- likes(sam,chips).
%% ?- likes(sam,curry).

likes(sam,Food) :- indian(Food), mild(Food).
likes(sam,Food) :- chinese(Food), mild(Food).
likes(sam,Food) :- italian(Food).
likes(sam,fish).
likes(sam,chips).

likes(ann,Food) :- mild(Food).

%likes(kim,F) :- not(mild(F)).
%likes(kim,F) :- (indian(F);chinese(F);italian(F)), not(mild(F)).

indian(curry).
indian(tandoori).
indian(kurma).

italian(manicotti).
italian(spaghetti).

chinese(sweet_sour).
chinese(szechwan).

mild(tandoori).
mild(kurma).
mild(sweet_sour).

:- not(mild(szechwan)).