(though I don't recommend hard-coding linenumbers there, use $DB::single=1 to set a breakpoint in place)

use strict;
use warnings;

push @DB::typeahead,
  'b 19 $y==3',
  '{ X y'
  if exists &DB::DB;


$|=1;

my $a;
our $y;


for (0..10) {
   print;
   $a++;
   $y++;
}
[download]

  DB<22> c
0123auto(-3)  DB<22> X y
$y = 3
auto(-2)  DB<23> b 19 $y==3
auto(-1)  DB<24> { X y
  DB<25> c
45678910auto(-1)  DB<25> X y
  DB<26>
[download]

> yes, it's still unclear for me if you want to step thru or run an automatic trace.

I think stepping thru the code would imply an interactive session. I am looking for an automatic trace, it would be nice to indicate which lines/variables should be printed, but having something that prints all of the variables modified and statements run would suffice. (huge output, but that isn't a problem!) There are some autotrace modules that may work, but I would like to accomplish this without additional modules. (lets make believe we are air gapped and getting to cpan is a problem)

> At least in .perldb with afterinit
sub afterinit { push @DB::typeahead, "b 4", "b 6"; }

So this isn't exactly thru the $ENV{PERLDB_OPTS} environment variable but using a file .perldb is easy enough to do. (though, @DB::typeahead is not a supported interface and is subject to change in future releases.)

I attempted the following:
echo "sub afterinit { push @DB::typeahead, \"a 119 p \$var\"; }" > .perldb

I see:

 29: main();
auto(-1) DB<1> a 199 p __DB<2> (some program output)
and then it shows 6556 segmentation fault  with exit code 139.
[download]

not sure what is causing the seg fault and I again lose the automatic printing of all the statements, but I see some of the program output. Hopefully the above typeahead gives you an idea of what I'm trying to accomplish.


Thanks again for all the thought and replies.

There is already a whole trace infrastructure apart from the debugger.

Please note the debugger IS eventually for interaction.

And I've shown you already 3 approaches, with varying details and footprint

• print when you break back to prompt {
• print whenever you pass a certain point with a or b
• print whenever you execute any statement with w

> push @DB::typeahead, \"a 119 p \$var\";

Please note again that a , b and w only take real Perl code

but p is a debugger command

Commands accepting debugger commands are documented with db_cmd or db_command

  DB<27> h {
{ db_command    Define debugger command to run before each prompt.
{ ?            List debugger commands to run before each prompt.
{{ db_command    Add to the list of debugger commands to run before ea
+ch prompt.
{ *             Delete the list of debugger commands to run before eac
+h prompt.
[download]

Cheers Rolf
_{(addicted to the Perl Programming Language and ☆☆☆☆ :)
Je suis Charlie!}

> I've shown you already 3 approaches, with varying details and footprint
I very much appreciate your responses!

> There is already a whole trace infrastructure apart from the debugger. the debugger IS eventually for interaction.
I've seen Devel::Trace but that also seems to only print the statements and not the data. If there is a whole trace infrastructure (/w data printing capabilities) outside of the debugger I am not aware of it and would appreciate a pointer if so.
http://dave.thehorners.com/tech-talk/programming/94-perl-programming