package UnderScore; use Carp; sub TIESCALAR { my $class = shift; my $dummy; return bless \$dummy => $class; } sub FETCH { croak "Read access to \$_ forbidden" } sub STORE { croak "Write access to \$_ forbidden" } sub unimport { tie($_, _ _PACKAGE_ _) } sub import { untie $_ } tie($_, _ _PACKAGE_ _) unless tied $_; 1;