Hi everyone,

My script is giving an error message:

Can't call method "set" on unblessed reference at ./oop-closures-objects line 9.

I can't find the reason, @INC is updated, the name of a module is Student.pm. It seems maybe the problem in a variable $access_type? But I can't find the answer, I'll be happy in any kind of a help-messages :-)

Code of package is:

package Student;
sub new { # Constructor
    my $class = shift;
    my $data={};
    our $students;

    my $ref = sub { # Closure
        my ($access_type, $key, $value) = @_;

        if ($access_type eq "set") {
                $data->{$key} = $value;  
                        # $data still available here
        }
        elsif ($access_type eq "get") {
            return $data->{$key};
        }
        elsif ($access_type eq "keys") {
            return (keys %{$data});
        }
        elsif ($access_type eq "destroy") {
            $students--;
            return $students;
        }
        else {
         die "Access type should be set or get";
        }
                print "New student created, we have ", 
                  ++$students, " students.\n";
        bless ($ref, $class);  
                  # bless anonymous subroutine
    }
} # End constructor

sub set {
    my ($self, $key, $value) = @_;  
            # $self reference anonymous sub
    $self->("set", $key, $value);
}

sub get {
    my ($self, $key) = @_;
    return $self->("get", $key);
}

sub display {
    my $self = shift;
    my @keys = $self->("keys");
    @keys=reverse(@keys);
    foreach my $key (@keys) {
      my $value = $self->("get", $key);
      printf "%-25s%-5s:%-20s\n", $self, $key, $value;
    }
    print "\n";
}

sub DESTROY {
  my $self = shift;
  print "Object going out of scope:\n";
  print "Students remain: ", $self->("destroy"), "\n";
}

1;
[download]

Code of a program that uses the Student.pm:

#!/usr/bin/perl -w
use lib("lib");
use Student;

$ptr1 = Student->new();  # Create new students
$ptr2 = Student->new();
$ptr3 = Student->new();

$ptr1->set("Name", "Jody Rogers"); # Set data for object
$ptr1->set("Major", "Law");

$ptr2->set("Name", "Christian Dobbins");
$ptr2->set("Major", "Drama");

$ptr3->set("Name", "Tina Savage");
$ptr3->set("Major", "Art");

$ptr1->display();  # Get all data for object
$ptr2->display();
$ptr3->display();

print "\nThe major for ", $ptr1->get("Name"), 
         " is ", $ptr1->get("Major"), ".\n\n";
[download]

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