Now here's the problem: when the player kills a foe called "a male elf soldier", it should turn into an item called "the corps of a male elf soldier". Therefor, I need to change the parent of this particular instance of Foe to Item.

Perhaps you'd find it easier to create a new Item, copying over the appropriate data from the Foe. That's what I'd do anyway.

Hmm... that tought has passed my mind in one way or another but I just didn't see the way how to do it. Now you've stated it like a simple thing, I indeed see how simple it is. I'll condsider it.

sub is_carryable {
    my $self = shift;
    if ( $self->is_alive() ) {
        # can't carry a live orc!
        return 0;
    } else {
        # dead body
        return 1;
    }
}
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Might be a good idea, altough in this case many of the methods will be in an if-else manner, just because the two things share a lot although they hardly share anything.

I know it might look like I'm rejecting all advises, I'm aware of that, but the 'multimorphing' idea as it seems to be called is not very usable I think.

What I'm suggesting is that you are thinking about it at the wrong level. What's important to your program might not be whether or not the object is a foe but rather whether or not it is carryable. Each kind of object may have unique rules about when it is carryable. In general, the idea is to push as much of the decision-making about how an object will behave in a certain situation into the object itself (by asking it with methods like this) rather than have some other code that decides what the object can do based on what type it is.

What's wrong with reblessing then? The variable keeping track of the actual type might be a good idea, but many of the methods will then look like

if ($somehow_is_a_foe) {
} else {
}
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because the two share a lot, although they hardly share anything.

Update: I have not yet thought about re-blessing. I think it's a good idea, worthwhile trying but if you say it's bad (or at least, will suck) I'll be glad to know why, just to find out if re-blessing is what I want.

No, I mean you plug it like this:

package Elf;
sub named {
  my $class = shift;
  bless {
    Name => shift;
    Actions => Elf::Live::,
    Has => {},
  }, $class;
}

sub die {
  shift->{Actions} = Elf::Dead::;
}

sub can_attack { # delegate to actions
  shift->{Actions}->can_attack(@_);
}

sub enemy_of {
  shift->{Actions}->enemy_of(@_);
}

package Elf::Live;

sub can_attack { ... }

sub enemy_of { ... }

package Elf::Dead;

sub can_attack { ... }

sub enemy_of { ... }
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A simple change of the Actions variable by plugging in a different "behavior container" causes a bank-switch of those behaviors to a new motif. I forget the "gang of four" pattern for this, but it's one of those. {grin}

-- Randal L. Schwartz, Perl hacker
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