An implementation of the findall relation.
Source: PROLOG programming for artificial intelligence, 3rd Edition, Harlow, 2001, ISBN 0-201-40375-7.
Program source code: findall.pl
% Figure 7.4 An implementation of the findall relation. findall( X, Goal, Xlist) :- call( Goal), % Find a solution assertz( queue(X) ), % Assert it fail; % Try to find more solutions assertz( queue(bottom) ), % Mark end of solutions collect( Xlist). % Collect the solutions collect( L) :- retract( queue(X) ), !, % Retract next solution ( X == bottom, !, L = [] % End of solutions? ; L = [X | Rest], collect( Rest) ). % Otherwise collect th e rest
RTERR: No permission to modify static procedure.