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Re: dumping variables automatically with their name?

by Rhandom (Curate)
on Mar 24, 2014 at 14:52 UTC ( #1079533=note: print w/replies, xml ) Need Help??


in reply to dumping variables automatically with their name?

There is another method to get the name other than pad walking or name passing. I used this method in the 11 year old CGI::Ex::Dump module (looks like the POD for that module is rather lackluster - guess I should update it after 11 years). We've used a variant of this for some time.

Whenever we debug we also like to see the line location - once we have parsed for the line location it is trivial to open the code and look for that line and do a very barebones parse. Apologist notes: This may not be academically correct, but we don't care - we're debugging. The output will also not be right if the source file changes, or the debug line is too complex - but again I don't care about a perfect solution - I want a fast good enough solution. Maybe someday we'll update it to a padwalker, but it is really rather trivial as it is. Here is a sample:

$ cat sample.pl use strict; use CGI::Ex::Dump qw(debug); my $a = 123; my @b = qw(1..10); my $obj = bless {}, __PACKAGE__; debug; debug $a, \@b, $obj; debug "Arbitrary String "x2; debug {"a".."f"}; $ perl sample.pl debug: sample.pl line 6 debug: sample.pl line 7 $a = 123; \@b = [ "1..10" ]; $obj = bless( {}, 'main' ); debug: sample.pl line 8 String = "Arbitrary String Arbitrary String "; debug: sample.pl line 9 {"a".."f"} = { a => "b", c => "d", e => "f" };
The actual dumping is done by Data::Dumper, so setting all Data::Dumper options will control the output. It should be easy enough to replace the output with Data::Dump, or Data::Dumper::Simple, or even JSON or YAML, or any of the other 100 ways to dump out data. We used Data::Dumper because 11 years ago it was what there was.

Internally we use a variation of this codebase called simply "Debug". By default debug goes to STDOUT, but we have variants called debug_warn that goes to STDERR and a debug_dlog variant that will go directly to our perl based system logger.

my @a=qw(random brilliant braindead); print $a[rand(@a)];

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Re^2: dumping variables automatically with their name?
by LanX (Cardinal) on Mar 31, 2014 at 19:54 UTC
    Thanks! :)

    ... took a look into the source...

    May I ask why you are reopening (i.e. reading again) the files if DATA is already pointing to them?

    Cheers Rolf

    ( addicted to the Perl Programming Language)

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