Creating a list out of rules

[bewmar]

I need to form a list of all members of an object that are defined by rules. Example:

has(face,eyes,2).
has(eyes,pupil,1).

I want to be able to extract the information in such a way that a predicate list_part would return all the attributes a certain object has. In the above example list_part(face,X) should return X = [eyes, pupil].

I've been going in circles on this one, any help is greatly appreciated.

 

[joel76]

If you have SWI-Prolog, take a look at bagof/setof.

 

[nn987]

well it's easy. Just do

has(face,eyes,2).
has(eyes,pupil,1).

list_part(X,Y,C):- findall(X,L,has(Y,L),C).