If you change SomeClass to read

  package SomeClass;
  use base qw(SomeOtherClass);
  ...
[download]

  sub run {
      my $self = shift;
      $self->SomeSub();
  }
[download]

Maybe I am misunderstanding, but I think you would be better off subclassing your original class and calling the parent constructor. If a subclass is innapropriate, then SomeOtherClass should instantiate its own SomeClass object, store it in $self and use accessors that way. With either strategy, your eval will use SomeOtherClass instead of SomeClass.

Cheers,
Ovid

Join the Perlmonks Setiathome Group or just click on the the link and check out our stats.

I think you might actually be asking the wrong question..... however...

If you really want to do this one way would be to re-bless the object into SomeOtherClass before the call. However this is almost certainly evil unless you're building some kind of state-transition pattern.

More likely is that you want to setup some kind of has-a relation with a SomeOtherClass object and pass the object as an argument.

Can you give more information on what you want SomeClass and SomeOtherClass to do? What is the relationship between the classes (and CGI)? Why don't you have SomeSub as a method of SomeClass?

I suspect that once you've clarified this some kind of has-a of is-a relationship between SomeClass and SomeOtherClass will become obvious...

I'm sorry. I'm still not understanding what you're trying to achieve. Probably me being dim... it's been known to happen...

Can you give concrete examples of SomeClass and SomeOtherClass? What is the relationship between them? What are you trying to do? How are they used?

Just some real names would help :-)

What is the reason for SomeSub being a method of SomeOtherClass rather than SomeClass?

• Is SomeOtherClass a kind of SomeClass (e.g. like HTML::LinkExtractor is a kind of HTML::Parser)?
• Does SomeClass use SomeOtherClass objects (e.g. like HTTP::Request uses LWP::UserAgent objects)?
• Is there some more complex relationship going on?

Without knowning more about what you're trying to achieve it's difficult to give more useful advice...

Let me make this a lot simpler: Is there a way to let multiple packages (with subs named the same) share one $self? My below example shows how I'd like to use this whole mess (see comments in the code for further details):

eval {
    my $foo = OurParentPackage->new;
    $SIG{__WARN__} = sub { die @_ };
    $foo->initialize;
    $foo->run;
};
if ($@) {
    print "content-type: text/html\n\n$@";
    exit;
}


package OurParentPackage;
sub new {
    bless { }, shift;
}
sub initialize {
    my $self = shift;
    require CGI;
    $self->{CGI} = new CGI;
    $self->{Config} = { 'this' => 'that' }; # config hash would be loa
+ded here.
    # and some 'global' stuff....
    $self->{script_build} = 1;
    $self->{script_version} = '1.0 alpha'; 
    return $self;
}
sub run {
    my $self = shift;
    if ($self->{CGI}->param('area') eq 'widgetone') {
        if ($self->{CGI}->param('act') eq 'add') {
            WidgetOne->add;
        }
        else {
            WidgetOne->default;
        }
    }
    elsif ($self->{CGI}->param('area') eq 'widgettwo') {
        if ($self->{CGI}->param('act') eq 'add') {
            WidgetTwo->add;
        }
        else {
            WidgetTwo->default;
        }
    }
    elsif ($self->{CGI}->param('area') eq 'widgetthree') {
        # etc....
    }
}


package WidgetOne;
sub default {
    my $self = shift;
    ############
    # the below line wont work because it needs the the above subs $se
+lf. I need to get its $self here somehow without re-running OurParent
+Package's initialize sub.
    print $self->{CGI}->header;
    ############
}
sub add {
    my $self = shift;
    # code to add a 'WidgetOne' would go here.
}


package WidgetTwo;
sub default {
    my $self = shift;
    # the default 'WidgetTwo' page code would be here...
}
sub add {
    my $self = shift;
    # code to add a 'WidgetTwo' would go here.
}


package WidgetThree;
sub default {
    my $self = shift;
    # the default 'WidgetThree' page code would be here...
}
sub add {
    my $self = shift;
    # code to add a 'WidgetTwo' would go here.
}
[download]