the only difference between each of the do_something methods are a couple of constants that I already know at compile time.

It matters who knows these constants. If these are only known in the "final" classes, then you can use a single do_something() inherited from the parent class, and then arrange for each of the specializing classes to provide methods to return the constants.

Let's consider a simple "B inherits from A" case.

  package A;

  sub new {
      my $pkg = shift;
      bless {}, $pkg;
  }

  sub do_something {
      my $self = shift;

      my $n = $self->x() + $self->y();
      print "something is $n\n";
  }

  sub x { die "subclass must override x\n" }
  sub y { die "subclass must override y\n" }

  package B;

  @ISA = (A);

  sub x { 42 }
  sub y { 47 }

  package main;

  my $object = new B();
  $object->do_something;
  # A::do_something invokes B::x and B::y
[download]

This adapts easily to multiple levels of inheritance. For example, the first level of inheritance can override x() and the next level can override y().

An alternative is to stuff the constants into the object's hash at initialization time.

  package A;

  sub new {
      my $pkg = shift;
      my $self = bless {}, $pkg;
      $self->init();
  }

  sub init { die "subclass must override init()\n" }

  sub do_something {
      my $self = shift;
      my $n = $self->{x} + $self->{y};
      print "something is $n\n";
  }

  package B;

  @ISA = (A);

  sub init {
    my $self = shift;
    $self->{x} = 42;
    $self->{y} = 47;
  }

  package main;

  my $object = new B();
  $object->do_something();
  # A::do_something reaches into the bag, and pulls out
  # numbers that B::init provided
[download]

In both cases, you could provide default behavior in the superclass.

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