I experienced something this morning with the delete function that didn't seem to make sense. Here is the code in which the weirdness occurred:

my %subs = ( path => [ @{$session{hierarchy_path}} ] );
$subs{bottom_path_term} = ${pop(@{$subs{path}})}{term};
if (@{$subs{path}}) { delete $subs{path}[$#{$subs{path}}]{id}; }
else { delete $subs{path}; }
[download]

Basically what is going on here is that I have an array of hashes that I want to manipulate without mutilating the orginal. The reference to the array is a value of one hash and I wanted to have a reference to the changed array be the value of another hash. (Maybe that's just a long way of saying that I wanted to make a copy of an array from one hash into a another hash.) Anyway, once I have a reference to the anonymous array, everything works as expected except the third line. Instead of deleting a key/value from the second hash (%subs), it deletes the key/value from the original hash (%session). I don't understand. If it was a problem with my dereferencing and referencing, I would expect pop to pop from the original hash but it doesn't. I used Data::Dumper to spew the structure of $session{hierarchy_path} both before and after this little snippet just to make sure I wasn't that crazy! Here's what it showed me:

Before:
 'hierarchy_path' => [
                                {
                                  'id' => 0,
                                  'term' => 'Top of Hierarchy'
                                },
                                {
                                  'id' => '57000',
                                  'term' => 'Education'
                                }
                              ],


After:
 'hierarchy_path' => [
                                {
                                  'term' => 'Top of Hierarchy'
                                },
                                {
                                  'id' => '57000',
                                  'term' => 'Education'
                                }
                              ],
[download]

Can anyone explain to me what's going on? BTW, I'm using Perl 5.6.1 on Linux