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From: Aleksandr Vinokurov on 20 Apr 2010 16:23
Hello all,

I did not understand what it is with the tracing of the recursion. I
have some file with this content:

----------------------
(defun foo (n)
(print n)
(when (plusp n) (foo (1- n))))

(defun bbb ()
(print "bbb"))

(defun aaa ()
(print "aaa")
(bbb))
----------------------

Then I compile it with C-c C-k and switch to REPL with C-c C-z, then
all happens this way out:

CL-USER> (trace foo aaa bbb)
(BBB AAA FOO)
CL-USER> (foo 10)
0[7]: (FOO 10)

10
9
8
7
6
5
4
3
2
1
0
0[7]: returned NIL
NIL
CL-USER> (aaa)
0[7]: (AAA)

"aaa"
1[7]: (BBB)

"bbb"
1[7]: returned "bbb"
0[7]: returned "bbb"
"bbb"
CL-USER> (defun bar (n) (print n) (when (plusp n) (bar (1- n))))
BAR
CL-USER> (trace bar)
(BAR)
CL-USER> (bar 3)
0[7]: (BAR 3)

3
1[7]: (BAR 2)

2
2[7]: (BAR 1)

1
3[7]: (BAR 0)

0
3[7]: returned NIL
2[7]: returned NIL
1[7]: returned NIL
0[7]: returned NIL
NIL
CL-USER>


Why it traces only the first call to FOO when it is compiled outside
the REPL? If I need to recompile the code with "tracing of the FOO
enabled", then how can I do this?

Your help will be appreciated.
From: Piotr Chamera on 20 Apr 2010 17:12
Aleksandr Vinokurov pisze:
> Hello all,
>
> I did not understand what it is with the tracing of the recursion. I
> have some file with this content:
>
> (...)
>
> Why it traces only the first call to FOO when it is compiled outside
> the REPL? If I need to recompile the code with "tracing of the FOO
> enabled", then how can I do this?

Because compiler made optimisation of tail recursion into iteration?

You can try

(declare (optimize (speed X) (safety Y) (debug Z)))

in your function with X, Y and Z you can find in documentation
of your CommonLisp implementation (probably Z = 3).
From: Aleksandr Vinokurov on 21 Apr 2010 02:49
Piotr Chamera <piotr_chamera(a)poczta.onet.pl> writes:

> Aleksandr Vinokurov pisze:
>> Hello all,
>>
>> I did not understand what it is with the tracing of the recursion. I
>> have some file with this content:
>>
>> (...)
>>
>> Why it traces only the first call to FOO when it is compiled outside
>> the REPL? If I need to recompile the code with "tracing of the FOO
>> enabled", then how can I do this?
>
> Because compiler made optimisation of tail recursion into iteration?
>
> You can try
>
> (declare (optimize (speed X) (safety Y) (debug Z)))
>
> in your function with X, Y and Z you can find in documentation
> of your CommonLisp implementation (probably Z = 3).

Yes, I've suggested that and have already tried to optimize for debug 3,
but it was speed 0 which was the case.

Thank you, Piotr.
From: Alan Malloy on 21 Apr 2010 05:44
Aleksandr Vinokurov wrote:
> Hello all,
>
> I did not understand what it is with the tracing of the recursion. I
> have some file with this content:
>
> ----------------------
> (defun foo (n)
> (print n)
> (when (plusp n) (foo (1- n))))
>
> (defun bbb ()
> (print "bbb"))
>
> (defun aaa ()
> (print "aaa")
> (bbb))
> ----------------------
>
> Then I compile it with C-c C-k and switch to REPL with C-c C-z, then
> all happens this way out:
>
> CL-USER> (trace foo aaa bbb)
> (BBB AAA FOO)
> CL-USER> (foo 10)
> 0[7]: (FOO 10)
>
> 10
> 9
> 8
> 7
> 6
> 5
> 4
> 3
> 2
> 1
> 0
> 0[7]: returned NIL
> NIL
> CL-USER> (aaa)
> 0[7]: (AAA)
>
> "aaa"
> 1[7]: (BBB)
>
> "bbb"
> 1[7]: returned "bbb"
> 0[7]: returned "bbb"
> "bbb"
> CL-USER> (defun bar (n) (print n) (when (plusp n) (bar (1- n))))
> BAR
> CL-USER> (trace bar)
> (BAR)
> CL-USER> (bar 3)
> 0[7]: (BAR 3)
>
> 3
> 1[7]: (BAR 2)
>
> 2
> 2[7]: (BAR 1)
>
> 1
> 3[7]: (BAR 0)
>
> 0
> 3[7]: returned NIL
> 2[7]: returned NIL
> 1[7]: returned NIL
> 0[7]: returned NIL
> NIL
> CL-USER>
>
>
> Why it traces only the first call to FOO when it is compiled outside
> the REPL? If I need to recompile the code with "tracing of the FOO
> enabled", then how can I do this?
>
> Your help will be appreciated.

The other option is to, rather than compile with C-c C-k, evaluate with
C-c C-c. This causes the function to be interpreted rather than
compiled, which fixes the trace behavior.

--
Cheers,
Alan (San Jose, California, USA)
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