package Base;
use strict;
use warnings;
our @ISA = qw();

sub new 
{
  my $this = shift;
  my $class = ref($this) || $this;
  my $self = {};
  bless $self, $class;
  $self->init(@_);
  return $self;
}

# default init, does nothing...
sub init {1;}

# get/set a scalar member variable
sub _gss { @_ > 2 ? $_[0]->{$_[1]} = $_[2] : $_[0]->{$_[1]}; }

sub throw
{
  my $self = shift;
  my($p,$f,$l) = caller();
  die "Exception at: ",$p,"->$f($l)\n  ",join('',@_);
}


1;
########################################
package MyObject;
use strict;
use warnings;
our @ISA = qw(Base);

sub init
{
  my($self) = @_;
  $self->someSetting('default value');
  return 1;
}

sub someSetting {shift->_gss('_myObject__someSetting',@_);}

sub someAction
{
  my($self) = @_;
  print "setting: ", $self->someSetting(), "\n";
}

1;
########################################
package main;
use strict;
use warnings;
my $obj = MyObject->new();
$obj->someAction();
$obj->someSetting('new setting');
$obj->someAction();

exit 0;