Here an example for association:
package Rider;
sub new {
my($pck, $name)=@_;
return bless { name => $name }, $pck;
}
This is a Rider-class with a "name"-attribute, you can create new instances with Rider->new("John Wayne").
Now a horse with a rider:
package Horse;
sub new {
my($pck, $horse_name, $rider_name)=@_;
return bless {
name => $horse_name,
rider => Rider->new($rider_name),
}, $pck;
}
You can create instances with Horse->new("Mr Ed", "John Wayne"). The created class will have a "rider"-attribute which is an instance (= blessed reference) of the rider-class.
So yes you simply store the object-references in your underlying data-structure.
And by the way: The reason I bless not directly into "Rider" and "Horse" namespaces but rather use the package-name that the constructor gets passed when called via e.g. Rider->new (you should NOT call it as Rider::new) is so that I can re-use the constructor in a derived class - read Damian's book if this is unclear.
hth |