You are looking something rather like the (appropriately, given the example) factory pattern. The "method" used to create an instance is the factory.

The following is based on Moritz' sample, cleaned up and tested: :-)

use strict;
use warnings;

package Car;

my %carByType;

sub new {
    my ($class, %opts) = @_;

    return bless \%opts, $class;
}


sub factory {
    my (%opts) = @_;

    die "Don't know how to make a new car"
        if !exists $opts{name} || !exists $carByType{$opts{name}};

    $carByType{$opts{name}}->new(%opts);
}


sub describe {
    my ($self) = @_;
    my ($make) = ref ($self) =~ m/^Car::(.*)/;

    print "$make $self->{name}\n";
}

sub REGISTER_TYPE {
    my ($type, $name) = @_;

    $carByType{$name} = $type;
}

package Car::BMW;

our @ISA = qw/Car/;

Car::BMW->REGISTER_TYPE('Z1');
Car::BMW->REGISTER_TYPE('Z3');

package main;

my $z1 = Car::factory(name => 'Z1');

$z1->describe();

[download]

Prints:

BMW Z1

[download]
True laziness is hard work

In reply to Re: Inheritance: parent class determine which child class to use? by GrandFather
in thread Inheritance: parent class determine which child class to use? by fbicknel

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