package Parent;

use strict;
use Child;

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

    my $self = bless( {
        _opts     => \%opts, # save parent options
        _children => []      # an array of children
    }, $class);

    return $self;
}

sub new_child {
    my ($self, %opts) = @_;

    my $child = Child->new(
        %{ $self->{_opts} }, # the saved parent options
        %opts                # the new child options
    );

    # save this child inside the parent object
    push @{ $self->{_children} }, $child;

    return $child;
}

1;

package Child;

use strict;

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

    my $self = bless( { _opts => \%opts }, $class );

    return $self;
}

1;

package main;

use strict;
use Parent;

# Create the parent object. We will create child objects
# with it and save those child objects within the parent.
my $p = Parent->new( foo => 1, bar => 2 );

# Create the first child. Pass an extra option in.
my $c1 = $p->new_child( baz => 3 );

# Create a second child. Give it different options.
my $c2 = $p->new_child( qux => 4, yeah => 5 );

# Iterate through children and see which options they got.
for my $child ( @{ $p->{_children} } ) {
    while ( my ($k, $v) = each %{ $child->{_opts} } ) {
        print "$k ==> $v\n";
    }
    print "\n";
}