The variable is not protected - perl

Question

i have this sources
first start.pl
use strict;
use warnings;
use hh;
print "Starting...\n";
my $abc={
VAL=>['alfa','beta'],
STUDENTS=>{
stud1=>{VAL=>['delta','gama']},
stud2=>{VAL=>['omega','upsilon']},
}
};
my $object=hh->new(catalog=>$abc);
and the package
package hh;
use strict;
use warnings;
sub new {
my $class=shift;
my $self={#_};
bless ($self,$class) ;
$self->_initialize("",['BEGIN']);
return $self ;
}
sub _initialize {
my $self=shift;
my $tab=shift;
my $carry=shift;
$tab=$tab."\t|";
if (defined $self->{VAL}){print "$tab Have val=",join(" ",#{$self->{VAL}}),"\n";push(#{$carry},#{$self->{VAL}})}
foreach my $k (sort {lc $a cmp lc $b} keys %{$self}){
print $tab,"carry=",$#{$carry}+1," "," ",$k,"\n";
if (ref($self->{$k}) eq 'HASH'){print "$tab Running initialize pentru $k\n";_initialize($self->{$k},$tab,$carry)}
}
return $self;
}
1;
the output is like this
Starting...
|carry=1 catalog
| Running initialize pentru catalog
| | Have val=alfa beta
| |carry=3 STUDENTS
| | Running initialize pentru STUDENTS
| | |carry=3 stud1
| | | Running initialize pentru stud1
| | | | Have val=delta gama
| | | |carry=5 VAL
| | |carry=5 stud2
| | | Running initialize pentru stud2
| | | | Have val=omega upsilon
| | | |carry=7 VAL
| |carry=7 VAL
Somehow i want to collect into an array the VAL arrays between top of tree and the walked element . Way the last VAL who is in the second level has 7 elements . I want to have only 2 elements (alfa and beta)
this is the expected output
Starting...
|carry=1 catalog
| Running initialize pentru catalog
| | Have val=alfa beta
| |carry=3 STUDENTS
| | Running initialize pentru STUDENTS
| | |carry=3 stud1
| | | Running initialize pentru stud1
| | | | Have val=delta gama
| | | |carry=5 VAL carry=5 (OK)
| | |carry=5 stud2
| | | Running initialize pentru stud2
| | | | Have val=omega upsilon
| | | |carry=7 VAL carry=5 (not ok this need only his values catalog alfa beta omega epsilon)
| |carry=7 VAL not ok (carry 3 only catalog alfa beta)
...

Answer 1

If you want to accumulate only the values in the current branch, you have to pass a copy of the carry array. [#$carry] dereferences the arrayref $carry and creates a new arrayref from the elements. I kept the original reference for the debug print at the end of the function. The more natural way would be to write $carry = [#$carry].
use strict;
use warnings;
package hh;
use Data::Dumper;
sub new {
my $class=shift;
my $self={#_};
bless ($self,$class) ;
$self->_initialize("",['BEGIN']);
return $self ;
}
sub _initialize {
my $self=shift;
my $tab=shift;
my $carry=shift;
$tab=$tab."\t|";
print "$tab _initialize() called with carry "," [",join(', ',#$carry),"]\n";
my $new_carry = [#$carry];
if (defined $self->{VAL}){
print "$tab Have found val=",join(" ",#{$self->{VAL}}),"\n";
print "$tab pushing ",join(" ",#{$self->{VAL}}),"\n";
push(#{$new_carry},#{$self->{VAL}})
}
print $tab," carry=",$#{$new_carry}+1," [",join(', ',#$new_carry),"]\n";
foreach my $k (sort {lc $a cmp lc $b} keys %{$self}){
if (ref($self->{$k}) eq 'HASH'){print "$tab Running initialize pentru $k\n";_initialize($self->{$k},$tab, $new_carry)}
}
print "$tab returning to previous level. carry was "," [",join(', ',#$carry),"]\n";
return $self;
}
package main;
print "Starting...\n";
my $abc={
VAL=>['alfa','beta'],
STUDENTS=>{
stud1=>{VAL=>['delta','gama']},
stud2=>{VAL=>['omega','upsilon']},
}
};
my $object=hh->new(catalog=>$abc);
This prints:
Starting...
| _initialized called with carry [BEGIN]
| carry=1 [BEGIN]
| Running initialize pentru catalog
| | _initialized called with carry [BEGIN]
| | Have found val=alfa beta
| | pushing alfa beta
| | carry=3 [BEGIN, alfa, beta]
| | Running initialize pentru STUDENTS
| | | _initialized called with carry [BEGIN, alfa, beta]
| | | carry=3 [BEGIN, alfa, beta]
| | | Running initialize pentru stud1
| | | | _initialized called with carry [BEGIN, alfa, beta]
| | | | Have found val=delta gama
| | | | pushing delta gama
| | | | carry=5 [BEGIN, alfa, beta, delta, gama]
| | | | returning to previous level. carry was [BEGIN, alfa, beta]
| | | Running initialize pentru stud2
| | | | _initialized called with carry [BEGIN, alfa, beta]
| | | | Have found val=omega upsilon
| | | | pushing omega upsilon
| | | | carry=5 [BEGIN, alfa, beta, omega, upsilon]
| | | | returning to previous level. carry was [BEGIN, alfa, beta]
| | | returning to previous level. carry was [BEGIN, alfa, beta]
| | returning to previous level. carry was [BEGIN]
| returning to previous level. carry was [BEGIN]