*trace-level*
is a special variable whose value is the current depth of tracing. The current value of *trace-level*
is printed before the function name during the output from tracing.
USER 8 > (defun fac (n) (if (<= n 1)
1
(* n (fac (1- n)))))
FAC
USER 9 > (trace fac)
FAC
USER 10 > (fac 3)
0 FAC > (3)
1 FAC > (2)
2 FAC > (1)
2 FAC < (1)
1 FAC < (2)
0 FAC < (6)
6