PATH DISTANCE FINDER

DOMAINS
node=symbol
distance=integer
PREDICATES
nondeterm link(node,node,distance)
nondeterm path(node,node,distance)
CLAUSES
link(a,b,4).
link(a,c,2).
link(b,g,5).
link(c,g,6).
link(c,d,5).
link(d,g,3).
path(S,D,TDist):-link(S,D,TDist).
path(S,D,TDist):-link(S,X,TD1),path(X,D,TD2),TDist=TD1+TD2.
GOAL
path(a,g,TotalDistance).