Debugging bigrat?

jabowery has asked for the wisdom of the Perl Monks concerning the following question:

The mystery is why "print" doesn't work for bigrat when entered in the debugger:

$ cat t
use bigrat;
print 1/3 + 1/4,"\n";                 # produces 7/12
$ perl -d t

Loading DB routines from perl5db.pl version 1.33
Editor support available.

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

main::(t:2):    print 1/3 + 1/4,"\n";                 # produces 7/12
                                                                      
+            DB<1> print 1/3 + 1/4,"\n"
0.583333333333333

                                                                      
+            DB<2> n
7/12
Debugged program terminated.  Use q to quit or R to restart,
  use o inhibit_exit to avoid stopping after program termination,
  h q, h R or h o to get additional info.  

$ perl -v

This is perl 5, version 14, subversion 2 (v5.14.2) built for x86_64-li
+nux-gnu-thread-multi
(with 75 registered patches, see perl -V for more detail)
[download]

Comment on Debugging bigrat? Download Code

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Re: Debugging bigrat? (perl5db.pl scope) by Anonymous Monk on Jun 02, 2013 at 05:14 UTC
The mystery is why "print" doesn't work for bigrat when entered in the debugger: scope is scope $ perl -de 1 Loading DB routines from perl5db.pl version 1.33 Editor support available. Enter h or `h h' for help, or `perldoc perldebug' for more help. main::(-e:1): 1 DB<1> use bigrat; DB<2> print 1/3 + 1/4,"\n"; 0.583333333333333 DB<3> use bigrat; print 1/3 + 1/4,"\n"; 7/12 DB<4> q [download]	[reply] [d/l]
Re^2: Debugging bigrat? (perl5db.pl scope) by jabowery (Beadle) on Jun 02, 2013 at 16:09 UTC
"scope is scope" but what you are really saying is that the debugger's scope is not the same as that of the program it is debugging. How can one activate bigrat in the debugger's scope?	[reply]
Re^3: Debugging bigrat? (perl5db.pl lexical scope) by Anonymous Monk on Jun 03, 2013 at 05:51 UTC
bigrat is lexically scoped , example `$ perl -E " { use bigrat; say 1/3+1/4; }; say 1/3+1/4; " 7/12 0.583333333333333` [download] perl5db.pl uses eval to execute code you type, and each eval is a new lexical scope This is one reason I don't deal with debuggers update: oh look, someone ran into this limitation before, see Debugger, use strict, use warnings and Are debuggers good? One idea, how to make lexical pragma global, hints ( pl_hints $^H %^H ), taint::all, but I kind of think any debugger shouldn't need help with this kind of stuff anyway, it should be a feature , but like I said, I don't use them	[reply] [d/l]
Re^3: Debugging bigrat? (perl5db.pl scope) by Anonymous Monk on Jun 03, 2013 at 04:53 UTC
How can one activate bigrat in the debugger's scope? I don't know, I never use the debugger (or debuggers). I imagine it might involve editing perl5db.pl or something else, maybe http://search.cpan.org/perldoc/perl5db.pl#DEBUGGER_STARTUP, see perldebug, perldebtut, perldebguts, or alternative debuggers like ebug	[reply]