Re: Re (tilly) 1: Inheriting object data

[archon]

i must be missing something.. i thought i _was_ creating an object in class Foo::Bar by calling the new method that it inherits from Foo. however, that thought seems incongruous with "I don't see why you want two objects." are you saying i don't want to create an object from the base class? i suppose that is an option.

i am open to any solution that lets me use the subclass with the data that i fed the base class without having to give this data to the base class.

[tilly]

Just construct an object in Foo::Bar directly without making something in Foo first and pass it the data. That object "is-a" Foo as well.

In other words my point is that the object you create in the base class Foo just seems to be a redundant object. It isn't used, it isn't necessary. I see no reason to not just lose it and then you have no problem left.

[archon]

ah, i see. in this example that i cooked up to demonstrate the problem it is not used. in my real program, it is.

the base class has login and password info that all the subclasses use. the base class also has a login method.

the effect i was trying to achieve was to only have to pass the data (login/password) once and have it stored in a core object from which all the derived objects inherited not only its methods, but object data. does that violate OO principles?

[tilly]

In your situation I might store the login and password information in global variables in the base class. You can even be clever about it and have the constructor take those globals as default values, but allow someone to override it.

An alternate approach is to use a has-a relationship. In that case Foo::Bar would not inherit from Foo, but would have a property that was an object of type Foo, and would have a login method like this:

sub login {
  my $self = shift;
  $self->{base_obj}->login(@_);
}