{
  package My::Logger;
  our @EXPORT = qw/log_message/;
  use parent qw/Exporter/;
  sub log_message {
    my ($message) = @_;
    print STDERR "$PACKAGE - $message";
  }
}
{
  package My::Script;
  # if these were separate files, we'd use "use My::Logger"
  My::Logger->import;
  # want this to say "My::Script - Hello"
  log_message("Hello");
}

##</code><code>##

{
  package My::Logger;
  sub import {
    my $PACKAGE = caller;
    no strict 'refs';
    *{"$PACKAGE\::log_message"} = sub {
        my ($message) = @_;
        print STDERR "$PACKAGE - $message";
      };
  }
}
{
  package My::Script;
  My::Logger->import;
  log_message("Hello");  
}

##</code><code>##

  use Sub::Name qw/subname/;
  do {
    no strict 'refs';
    my $name = "$PACKAGE\::log_message";
    *{$name} = subname $name => sub { ... };
  };