Andy Wingo <wi...@pobox.com> writes:
> scheme@(guile-user)> ,tr (fibo 5)
> #<program 8c74200 at system/vm/trace.scm:30:6 ()>
> * #<program 8c74240 at <unknown port>:0:1 ()>
> * fibo 5
> ** fibo 4
> *** fibo 3
> **** fibo 2
> **** fibo 1
> *** fibo 2
> ** fibo 3
> *** fibo 2
> *** fibo 1
> #<program 8c741e0 at system/vm/trace.scm:31:6 ()>
> vm-trace-off! #<vm 8904680>
>
> Sweet, no?
Hi Andy,
Interesting stuff!
But I'm not sure. To me it seems less nice than the version that I
recently posted.
- Why are those #<program> and vm-trace-off! lines there?
- What if the function that you want to trace is not the one that you
want to invoke at top level?
- What if you want to trace several functions within a given
computation?
- Alternatively, if ,tr is supposed to mean "trace everything within
this computation", why aren't there trace lines for the applications
of `or', `=' and so on?
> We don't have return values here unfortunately, but that
> could be arranged.
Yes, I believe they are useful too.
> Now this too:
>
> scheme@(guile-user)> ,pr (fibo 30)
What would someone typing that actually be looking for? I would guess:
something about the timings of the internal parts of fibo ...
> % cumulative self
> time seconds seconds name
> 100.00 0.29 0.29 fibo
> 0.00 0.29 0.00 top-repl
> 0.00 0.29 0.00 call-with-backtrace
> 0.00 0.29 0.00 #<program 8caeb40 ()>
> 0.00 0.29 0.00 #<program 8ca10e0 opts>
> 0.00 0.29 0.00 start-repl
> 0.00 0.29 0.00 #<program 89f3420 at ice-9/boot-9.scm:3394:10
> ()>
> 0.00 0.29 0.00 #<program 8ca13d0 at
> system/repl/repl.scm:87:9 ()>
> ---
> Sample count: 23
> Total time: 0.29 seconds (0 seconds in GC)
... but there is nothing here at a finer-grained level than fibo
itself. So I'm afraid I don't see the usefulness, yet.
> Unfortunately (make-stack ...) doesn't actually do anything right now,
> so we see the whole continuation. Also unfortunately we don't see subrs
> on the stack, like dynamic-wind. But hopefully these problems will be
> fixed within a couple weeks.
Cool. But I think the key thing is generating the internal information
that the user would really want. Perhaps that requires a more complex
example.
Regards,
Neil
