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

for (qw(literal1 literal2 literal3))
{
	print "$_\n";
	foo('wilma');
}

sub foo
{
	Internals::SvREADONLY($_, 0);
	$_ = 'fred';
	goto &bar;
}

sub bar
{
	my ($name) = @_;
	print "foo --> name = $name, \$_ = $_\n";
}

__END__
literal1
foo --> name = wilma, $_ = fred
literal2
foo --> name = wilma, $_ = fred
literal3
foo --> name = wilma, $_ = fred

##</code><code>##

perl -E'say for sort keys %Internals::'