Link a variable to a class attribute in Perl - perl

Question

This question was born out of another (Completely destroy all traces of an object in Perl). After seeing some of the comments I believe I have narrowed the problem down to the "real" issue.
I'm looking for a simple way to link a variable to a class attribute in Perl so that whenever the attribute is modified, the variable will be automatically updated.
ex (some pseudo code):
# Create a file object
my $file = File->new();
# Get the text
my $text = $file->text();
# prints 'hello'
print $text;
# Set the text
$file->text('goodbye');
# prints 'goodbye'
print $text;
Also I want the $text variable to be read only so that you cannot inadvertently modify the text attribute of the file.

Answer 1

Use tie:
#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };
{ package File;
sub new {
bless ['hello'], shift
}
sub text {
my $self = shift;
if (#_) {
$self->[0] = shift;
} else {
return $self->[0]
}
}
}
{ package FileVar;
use Tie::Scalar;
use parent qw( -norequire Tie::StdScalar );
sub TIESCALAR {
my ($class, $obj) = #_;
bless \$obj, $class
}
sub FETCH {
my $self = shift;
${$self}->text()
}
sub STORE {
die 'Read only!';
# Or, do you want to change the object by changing the var, too?
my ($self, $value) = #_;
${$self}->text($value);
}
}
my $file = 'File'->new();
tie my $text, 'FileVar', $file;
say $text;
$file->text('goodbye');
say $text;
# Die or change the object:
$text = 'Magic!';
say $file->text;