perl: a way to see a sub code in debug mode: perl -de 0 ?

Shell Programming and Scripting
1

Is there a way to see or print a sub code?

Sometime a sub could be already defined, but in the debug mode (so, interactively) it could be already out of screen.
So, I would think about a way to check if the sub is defined (just 'defined' is not a problem) and how it is defined.

Also, if some modules were used, the same check would be useful

For example, is there a way to print out the pr()-code in followed:

~/develop/src> perl -de 0

Loading DB routines from perl5db.pl version 1.28
Editor support available.

Enter h or `h h' for help, or `man perldebug' for more help.

main::(-e:1):   0
                               
  DB<1> sub pr { \
  cont: print ">"; printf @_; print "\n<\n";\
  cont: }

  DB<3> pr "arg are: %s %d %f", "string", 123, 3.12
>arg are: string 123 3.120000
<
                             
  DB<4> pr yes if defined &pr
>yes
<
2 
#!/usr/bin/perl

sub asdf($)
{
        shift;
        return 0;
}

if(defined("asdf"))
{
        print "asdf is defined\n";
}
3

How about this:

$ perl -de 0

Loading DB routines from perl5db.pl version 1.28
Editor support available.

Enter h or `h h' for help, or `man perldebug' for more help.

main::(-e:1):   0
  DB<1> sub pr { \
  cont: print ">"; printf @_; print "\n<\n";\
  cont: }


  DB<2>
  DB<2> pr "arg are: %s %d %f", "string", 123, 3.12
>arg are: string 123 3.120000
<

  DB<3> S pr
IO::Handle::print
IO::Handle::printf
IO::Handle::printflush
main::pr
  DB<4> l
1==>    0
  DB<4> l main::pr
Switching to file '(eval 13)[/usr/lib/perl5/5.8.8/perl5db.pl:628]'.
2       sub pr {
3:      print ">"; printf @_; print "\n<\n";
4       };
  DB<5>
1 Like
4

Perderabo:
Amaizing!
What the commands are the 'l' and 'S'?
The 'S' I guess, kind of 'search'?

OK, I have found: that is the debugger commands!

Anyway, BIG THANK YOU!
That exactly what I was looking for!

5

I have reviewed the debugger section in Larry Wall's Programming Perl book. He does come out and explicitly say why S and l are so named. Reading between the lines, I think that "S" might stand for "subroutines" and "l" seems to be chosen from "listing".