I have a little doubt about OO terminology. we all know that we can do:

package Foo;

sub bar {
    print "Foo::bar!\n";
}

package main;

my $x = 'Foo';

$x->bar();
[download]

but how do you call $x? it is just a string, which represents a package name. so it doesn't seems a "class reference". maybe a "symbolic class reference"?

I came across this trying to implement an object hierarchy in which I can have several "backend" classes and a "frontend" object. now, I don't need to instantiate backend objects, I only need to know which backend the main object refers to. so I thought something like this:

package Thing;

sub new {
    my($class, %option) = @_;
    my $self = {
        backend => "Thing::Backend::".$option{backend},
    };
    return bless $self, $class;
}

sub backend {
    my($self) = @_;
    return $self->{backend};
}

package Thing::Backend::A;

sub do {
    print "doing A\n";
}

package Thing::Backend::B;

sub do {
    print "doing B\n";
}

package Thing::Backend::C;

sub do {
    print "doing C\n";
}

package main;

my $x = Thing->new( backend => 'A' );

$x->backend->do();
[download]