I have a couple of situations where I'm trying to store data as objects and then pass the data on to another subroutine. My data structures end up becoming a bit complicated and I'm having trouble retrieving the data. Below is a simplified example where I'm inventorying batches documents by volume and page ranges. Along the way I also need to look for page gaps. What I've done is created an object called batch_inventory with the elements ranges and gaps. The ranges element will be an array of page_range objects. Each "page_range" object contains "volume", "start page" and "end page" elements. For simplicity's sake I'm just assigning numeric values to each element of the page_range object. Example code is below. When I execute the code I get the error: Can't use string ("3") as a HASH ref while "strict refs" in use at obj_test.pl line 21. It looks like trying to access an array of hashes results in the structure being collapsed into a single long array. I can't seem to figure out a way to make this work. If at all possible, I need to make these data structures work without altering my overall process.

#!/usr/bin/perl
use strict;
use warnings;

my $inv = batch_inventory->new();

my @ranges;

for (my $c = 1; $c < 9; $c+= 3) {
  my $range = page_range->new();
  $range->{vol} = $c;
  $range->{start_pg} = $c+1;
  $range->{end_pg} = $c+2;
  push (@ranges,$range);
} 

$inv->{ranges} = @ranges;


foreach my $range ($inv->{ranges}) {
  print "$range->{vol} $range->{start_pg} $range->{end_pg}\n";
}

exit (0);

########## Objects ##########
package page_range;
sub new {
  my $class = shift;
  my $self = {
     vol => undef,
     start_pg => undef,
     end_pg => undef
  };
  bless $self, $class;
  return $self;
}

package batch_inventory;
sub new {
  my $class = shift;
  my $self = {
    ranges => undef,
    gaps => undef
  };
  bless $self, $class;
  return $self;
}
[download]