#!/usr/bin/perl
use strict;
use warnings;

package Foo;

sub method {
    routine();
}

sub routine {
    return __PACKAGE__;
}


package Foo::Bar;
our @ISA = qw( Foo );

sub routine {
    return __PACKAGE__;
}

sub method {
    no warnings 'redefine';
 
    # Temporarily override routine() in the parent class.
    local *Foo::routine = \&routine;
    
    # Delegate to parent method.
    my $self = shift;
    $self->SUPER::method(@_);
}

package main;
print "Foo:      ", Foo->method, "\n";
print "Foo::Bar: ", Foo::Bar->method, "\n";
print "Foo:      ", Foo->method, "\n";