$ clisp

<...snip...>

[1]> (load "arithmetic.l")
;; Loading file arithmetic.l ...
;; Loaded file arithmetic.l
T
[2]> :(trace sum)
:||
[3]>
;; Tracing function SUM.
(SUM)
[4]> :(trace product)
:||
[5]>
;; Tracing function PRODUCT.
(PRODUCT)
[6]> (sum '())
1. Trace: (SUM 'NIL)
1. Trace: SUM ==> 0
0
[7]> (sum '(200))
1. Trace: (SUM '(200))
2. Trace: (SUM 'NIL)
2. Trace: SUM ==> 0
1. Trace: SUM ==> 200
200
[8]> (sum '(2 3 5 7 11 13 17 19))
1. Trace: (SUM '(2 3 5 7 11 13 17 19))
2. Trace: (SUM '(3 5 7 11 13 17 19))
3. Trace: (SUM '(5 7 11 13 17 19))
4. Trace: (SUM '(7 11 13 17 19))
5. Trace: (SUM '(11 13 17 19))
6. Trace: (SUM '(13 17 19))
7. Trace: (SUM '(17 19))
8. Trace: (SUM '(19))
9. Trace: (SUM 'NIL)
9. Trace: SUM ==> 0
8. Trace: SUM ==> 19
7. Trace: SUM ==> 36
6. Trace: SUM ==> 49
5. Trace: SUM ==> 60
4. Trace: SUM ==> 67
3. Trace: SUM ==> 72
2. Trace: SUM ==> 75
1. Trace: SUM ==> 77
77
[9]> (product '())
1. Trace: (PRODUCT 'NIL)
1. Trace: PRODUCT ==> 1
1
[10]> (product '(200))
1. Trace: (PRODUCT '(200))
2. Trace: (PRODUCT 'NIL)
2. Trace: PRODUCT ==> 1
1. Trace: PRODUCT ==> 200
200
[11]> (product '(2 3 5 7 11 13 17 19))
1. Trace: (PRODUCT '(2 3 5 7 11 13 17 19))
2. Trace: (PRODUCT '(3 5 7 11 13 17 19))
3. Trace: (PRODUCT '(5 7 11 13 17 19))
4. Trace: (PRODUCT '(7 11 13 17 19))
5. Trace: (PRODUCT '(11 13 17 19))
6. Trace: (PRODUCT '(13 17 19))
7. Trace: (PRODUCT '(17 19))
8. Trace: (PRODUCT '(19))
9. Trace: (PRODUCT 'NIL)
9. Trace: PRODUCT ==> 1
8. Trace: PRODUCT ==> 19
7. Trace: PRODUCT ==> 323
6. Trace: PRODUCT ==> 4199
5. Trace: PRODUCT ==> 46189
4. Trace: PRODUCT ==> 323323
3. Trace: PRODUCT ==> 1616615
2. Trace: PRODUCT ==> 4849845
1. Trace: PRODUCT ==> 9699690
9699690
[12]> (bye)
Bye.