What is an unblessed reference error?

[Wiinie]

How can I fix the error "Can't call method "id" on unblessed reference" for the following code?

sub language{
    my $self = shift;
    if (!$self->{LANGUAGE})
    {
        my @language = ();
        my $statement = $db->prepare("select  languageId, languageName
                                        from language");
        $statement->execute();
 
        while(my @array = $statement->fetchrow_array()){
            my ($id , $name) = @array;
            my $object = Language->new();
            $object->id($id);
            $object->name($name);
            push (@language, $object);    
        }            
        $self->{LANGUAGE} = \@language;
    }
    return $self->{LANGUAGE};
}
 
my @languagetest = language();
 
            foreach my $current(@languagetest){
            my $id = $current->id();
            my $name = $current->name();
            print "RETURN ID: [$id]  Name: [$name] \n";
            }

[miller]

You do not show the code where the problem occurs. You create an object there:

my $object = Language->new();
 

Therefore in the new method of the Language class, you should be returning a blessed data structure as is required in perl OOP (Object Oriented Prgramming). Where's your new method? are you blessing a hash or such?

perldoc: perltoot - Tom's object-oriented tutorial for perl

- Miller

[Wiinie]

I try using foreach to print out the result

# my @languagetest = language();
#  
#             foreach my $current(@languagetest){
#             my $id = $current->id();
#             my $name = $current->name();
#             print "RETURN ID: [$id]  Name: [$name] \n";
#             }
 

and it gives me an error of unblessed reference when i call the method id() again.. please help me to solve this problem. or does it have another to print out the result.

[miller]

Yes, because $current is not an object. You should know what type of data structure $current is, but if you don't use Data::Dumper

use Data::Dumper;
 
my @languagetest = language();
 
foreach my $current (@languagetest) {
    print Dumper($current);
    my $id = $current->id();
    my $name = $current->name();
    print "RETURN ID: [$id] Name: [$name] \n";
}

[Wiinie]

Thank so very much for the above answer.
And I have another question as well. I did use the selectall_array_ref to execute this query. and when I try to print in the sub nextWords. it does work and prints out all the result that i have expected.

sub nextWords {
    my ($id, $offset) = @_;
    my @array = ();
    my $statement = $db->selectall_arrayref("select word from words 
            left outer join language
            on words.languageId = language.languageId
            where words.languageId = $id
            order by word asc
            limit 10 offset $offset;");
 
    my @main= ();
    foreach my $i (@$statement)
    {
        push(@main, @{$i}[0]);
    }
    @array[$id] = [@main];
 
    return  @array; 
}    
 
my $lang_size = languages();
for my $id(1 .. $lang_size ){
 
    print "=======ID = " . $id . "=======\n";
    my $self->{CURRENTOFFSET}  = 0;
    NAME: while (1 > 0){
        my @newwordsList = nextWords($id,$self->{CURRENTOFFSET});
 
        $self->{CURRENTOFFSET}+= 10;
 
        foreach my $k (@{@newwordsList[$id]}) {
            print $k . "\n";
        }
        print "\n";
        if (!@{@newwordsList[$id]}[0]) {
            last NAME;
        }
    }
}

However, when i try to print out by create and other file.pl to compile it. it doesnt work, it give an error "DBD::SQLite::db selectall_arrayref failed: unrecognized token: "0x1db16c".

$object = DataLayer->new();
print $object->nextWords();
 
for my $id( 1 .. 3)
    {
        my $offset= 0;
        NAME: while (1>0)
        {
            my @wordList = $object->nextWords($id, $offset);
            $offset+=10;
            foreach my $k (@{@wordList[$id]}) {
            print $k . "\n";
            }
            if (!@{@wordList[$id]}[0]) {
            last NAME;
            }
        }    
    }
 

thanks in advance..