2005-10-12 sum Comp う〜ん、某Prologのassignment 3の4。 sum( , 0 ). sum( [iyada | R], S) :- sum( , 0 ), !. sum( [X | Rest], S ) :- iyada == X. sum( [X | Rest], S ) :- sum(Rest, S1), integer( X ), S is S1 + X.