% file: enumerate.pro 
% author: Robert Keller 
% purpose: relation enumeration utility 
% show shows an enumerated relation, one tuple per line 

show(Relation) :- 
    enumerate(Relation, List), 
    list(List). 

% enumerate enumerates a named relation to produce a list

enumerate(Relation, List) :- 
    current_predicate(Relation, Form), 
    Form =..[Relation | Args], 
    (setof(Args, Form, List) ; List = []). 

% list shows a list, one element per line 

list([]). 
list([A | X]) :- 
    write(A), 
    nl,
    list(X).