You've already hit on my major objection to it: You shouldn't be saying that an Obj isa Foo and an Obj isa Bar if an Obj is neither a Foo nor a Bar.

The traditional way of resolving this would be with aggregation, in which Obj has a Foo and a Bar which it delegates calls to: 

package Obj;

sub new {
  ...
  $self->{_foo} = Foo->new;
  ...
}

sub foo {
  my $self = shift;
  return $self->{_foo}->foo(@_);
}

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If you want to dip your toes into the Moose water (eeeeew...), this may be a good place to use roles, depending on what you actually want to accomplish in the real world. If you want to just pull behaviour from Foo/Bar, but still have it operate on the Obj's data, then roles are likely a good match. If you need to have independent Foo/Bar data as well as their behaviour, then it's likely that aggregation would be a more appropriate model.

An object is the class it inherits from, has objects it aggregates, and does roles it consumes.

In reply to Re: Designing an OO program with multiple inherited classes by dsheroh
in thread Designing an OO program with multiple inherited classes by punkish

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