Good Morning Monks,

This is a question about error tracking.. Say I'm reading in various variables from various files, and passing them to various different subs in various different modules I wrote. Then say that some of my input data (in the input files) is messed up in some way. So I pass it to one of my subs, and the sub throws an error (lets have an example because I'm confusing myself here :P)

(main.pl)
use strict;
use warnings;
use mySubs;

my @array;

while (my $temp=<INPUT>){
    my $number=&mySub(\$temp);
    @array=(@array,$number);
}
---------------------------
(mySubs.pm)
use strict;
use warnings;
package mySubs;
#...Exporter.. etc..

sub mySub
{
  my $variable = ${$_[0]};
....
#some stuff
....
  if (some condition){
     print "data $variable not valid in mySub\n";
     return -1;
  }
....
#rest of sub
....
}
[download]

So what I want to be able to do is instead of just printing 'data $variable not valid in mySub' I'd like to be able to print 'data $variable not valid in mySub from line xx in 'main.pl'; line yy in <INPUT>'

Is this possible? I thought I could pass $. around but that wouldn't (I don't think) tell me it came from 'main.pl' (And it would be a pain to change all of my subs if there's a simpler way!)

I don't even really know where to start on this one, so any monk-ish wisdom would be appreciated!
Cheers, why bird.

p.s. I wasn't sure what an appropriate title would be so feel free to change it/suggest what it should be changed to