Is it possible – in the core inform language or by an existing extension – to have a relation that is multivalued rather than just on/off? For example, a person could like something, dislike it, or (the default) be indifferent to it.
I know it’s possible to set this up using two relations:
Liking relates various people to various people.
The verb to like (he likes, they like, he liked, it is liked, he is liking) implies the liking relation.
Disliking relates various people to various people.
The verb to dislike (he dislikes, they dislike, he disliked, it is disliked, he is disliking) implies the disliking relation.
But this makes it possible for someone to both like and dislike something at the same time, and requires the coder to always remember to change both relations at once:
now Spot likes the red chew toy;
now Spot does not dislike the red chew toy; [unfortunately not redundant...]
Any known way to make this into a single three-state relation rather than a pair of two-state ones?