Tracing Function Calls

There is a trace package that allows tracing function calls:

(load-file "cs378/trace.clj")
user=> (trace (* 2 3))
TRACE: 6
6 

(deftrace factorial [n]
  (if (= n 0) 1 (* n (factorial (- n 1)))))
user=> (factorial 4)
TRACE t256: (factorial 4)
TRACE t257: | (factorial 3)
TRACE t258: | | (factorial 2)
TRACE t259: | | | (factorial 1)
TRACE t260: | | | | (factorial 0)
TRACE t260: | | | | => 1
TRACE t259: | | | => 1
TRACE t258: | | => 2
TRACE t257: | => 6
TRACE t256: => 24
24