1% generated: 17 November 1989 2% option(s): SOURCE_TRANSFORM_1 3% 4% tak 5% 6% Evan Tick (from Lisp version by R. P. Gabriel) 7% 8% (almost) Takeuchi function (recursive arithmetic) 9 10top:-tak. 11 12tak :- tak(18,12,6,_). 13 14tak(X,Y,Z,A) :- 15 X =< Y, 16 Z = A. 17tak(X,Y,Z,A) :- 18 X > Y, 19 X1 is X - 1, 20 tak(X1,Y,Z,A1), 21 Y1 is Y - 1, 22 tak(Y1,Z,X,A2), 23 Z1 is Z - 1, 24 tak(Z1,X,Y,A3), 25 tak(A1,A2,A3,A). 26