Ciao monks.

I have been trying to improve my perl skills for a few months and one area I don't understand is the 'tie' function.

package Queue;
use warnings;
use strict;

sub TIESCALAR {
  my $class = shift;
  my @data  = split ' ', $_[0];
 
  bless( \@data, $class );
  return \@data;
}

sub STORE {
  my $obj   = shift;
  my $data  = shift;
  push @$obj, $data;
}

sub FETCH {
  my $obj = shift;
  
  return shift( @$obj );
}

return 1;
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use warnings;
use strict;
use Queue;

my $line;

tie( $line, 'Queue', 'a b c d' );

print $line, "\n";
print $line, "\n";
print $line, "\n";
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Output:

C:\Perl\bin>perl myqueue.pl
a
b
c

C:\Perl\bin>
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I don't understand how this program works.
Could you please explain it to me?

Thanks,
Ciao, Alexa