Current:
listMoviesByRank(DB, L) :- DB=placeholder, L=placeholder.
Proposed:
listMoviesByRank(DB, L) :- db(DB), L=placeholder.
This way it might return X=placeholder when queried, which is more in line with the other pre-definitions. db/1 is defined anyway in database.pl of Ex7. At the moment it rather complains about an impossible unification here, while the others don't do this.
Current:
listMoviesByRank(DB, L) :- DB=placeholder, L=placeholder.Proposed:
listMoviesByRank(DB, L) :- db(DB), L=placeholder.This way it might return X=placeholder when queried, which is more in line with the other pre-definitions.
db/1is defined anyway in database.pl of Ex7. At the moment it rather complains about an impossible unification here, while the others don't do this.