$_ = 'hi';
my $code = sub { print $_->{blah} . "\t" . $_->{moo} . "\n" };
Bar::hi($code);
print $_ . "\n";    # prints 'hi'

package Bar;

sub hi {
  my $coderef = shift;
  local $_ = { 'foo' => 2, 'blah' => 5, 'moo' => 'blah' };
  &$coderef;  # prints '5      blah'
}