Thanks, you answered my question.  I’m educating myself in ways to debug 
Scheme, coming from an imperative background.  

I suspect the solution would be to leave the trace statements in and use a 
conditional when delivering production code.


> On Mar 21, 2020, at 2:27 PM, John Clements <cleme...@brinckerhoff.org> wrote:
> 
> It sounds like you’re looking for a way to have the trace inserted for you by 
> a debugging tool, so you don’t have to remember to take it out again later. 
> This wouldn’t be hard to do, but (as far as I know) no one’s taken the time 
> to do it.
> 
> John
> 
>> On Mar 21, 2020, at 8:43 AM, Nicholas Papadonis 
>> <nick.papadonis...@gmail.com> wrote:
>> 
>> I was successful with MIT Scheme placing (trace proc) inside the closure of 
>> this code.  Placing (trace proc) outside the closure did not have any effect.
>> 
>> This is the question I'm asking.  Is it possible to trace without modifying 
>> the closure?
>> 
>> I ask due to forward thinking about software engineering practices and 
>> modifying code (although it could be argued in C a preprocessor block could 
>> be placed to compile in or out conditional macros blocks).
>> 
>> Thanks again
>> 
>> On Sat, Mar 21, 2020 at 11:24 AM Ben Greenman <benjaminlgreen...@gmail.com> 
>> wrote:
>> On 3/21/20, dgtlcmo <nick.papadonis...@gmail.com> wrote:
>>> Does anyone know how to trace functions inside a closure?  I would like to
>>> trace hanoi-move, however find that with MIT Scheme I need to place (trace)
>>> 
>>> within the closure (hanoi n), otherwise the trace will not occur.
>>> 
>>> Can a trace like this be performed in Racket?
>>> 
>>> Thanks
>>> 
>>> (define (hanoi n)
>>>  (define (pmd from to)
>>>    (display "Move ")
>>>    (display from)
>>>    (display " to ")
>>>    (display to)
>>>    (newline)
>>>    '())
>>>  (define (hanoi-move n from to spare)
>>>    (cond ((= n 0) '())
>>> ((= n 1) (pmd from to))
>>> (else
>>>  (hanoi-move (- n 1) from spare to)
>>>  (hanoi-move 1 from to spare)
>>>  (hanoi-move (- n 1) spare to from))))
>>>  (hanoi-move n "A" "B" "C"))
>> 
>> Yes, Racket has trace tools:
>> https://docs.racket-lang.org/reference/debugging.html
>> 
>> Try adding (trace hanoi) before the call to (hanoi-move ....) at the bottom
>> 
>> -- 
>> You received this message because you are subscribed to the Google Groups 
>> "Racket Users" group.
>> To unsubscribe from this group and stop receiving emails from it, send an 
>> email to racket-users+unsubscr...@googlegroups.com.
>> To view this discussion on the web visit 
>> https://groups.google.com/d/msgid/racket-users/CAKD0t1%2Bn_W7%3Dc7%3D_KAcFuJQrFo86JBx8uGJuBfXY%2BgZrDFKHWg%40mail.gmail.com.
> 
> 
> 

-- 
You received this message because you are subscribed to the Google Groups 
"Racket Users" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to racket-users+unsubscr...@googlegroups.com.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/racket-users/38078F54-CD65-4223-852D-1D142C001F18%40gmail.com.

Reply via email to