Here is your module implemented as an inside-out class:
package MyMod;

use strict;
use warnings;
use Carp;
use Scalar::Util qw(refaddr);

# Have a private hash for each attribute
my %atr1;    # Attribute 1
my %atr2;    # Attribute 2
             # etc.
             
# This hash is used by the general purpose accessors
my %hashrefs = ( atr1   => \%atr1,
                 atr2   => \%atr2,
                 #etc 
                );
                    

sub new {
  my $class = shift;
  my %args = @_;
  
  # create some unique number from a reference
  my $self = \do{my $dummy};
  my $key = refaddr($self);
  
  $atr1{$key} = $args{'atr1'};
  $atr2{$key} = $args{'atr2'};
  # more attributes...
  
  
  bless($self, $class);
  # ... some code to populate attribs from passed parms
  return $self;
}

# General purpose get/set

sub set {
   my ($self, $attr, $value) = @_;
   my $key = refaddr $self;
      
   if (exists $hashrefs{$attr} ) {
      $hashrefs{$attr}{$key} = $value
   }
   else {
      carp "Invalid attribute name $attr"
   }
}

sub get {
   my ($self, $attr) = @_;
   my $key = refaddr $self;
   
   
   if (exists $hashrefs{$attr} ) {
      return $hashrefs{$attr}{$key}
   }
   else {
      carp "Invalid attribute name $attr";
      return;
   }
}

# MUST have a destructor
sub DESTROY {
    my ($self) = @_;
    my $key = refaddr $self;
      
    delete $atr1{$key};
    delete $atr2{$key};
    # likewise for other attribute hashes
}

1;

[download]
And here is the user code:
use strict;
use warnings;

use MyMod;
my $mm = MyMod->new(atr1 => 1, atr2 => 'string2');

print $mm->get('atr1')."\n";
print $mm->get('atr2')."\n";
$mm->set('atr1', 42);
print $mm->get('atr1')."\n";

$mm->{atr1} = 3000;    <<<<---- Fails "Not a HASH reference"

[download]

In reply to Re: Prevent direct acces to object's attributes by cdarke
in thread Prevent direct acces to object's attributes by vitoco

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.