require Tie::Hash;
use vars qw( %h %t );
%h = ( a=>1 );
tie %t, 'Tie::StdHash';
%t = ( z=>9 );
eval { sub { values %h }->() += 10; };
warn "$@\n";
eval { sub { values %t }->() += 10; };
warn "$@\n";
print ref(\substr("hello",1,2)), $/;
print ref(\sub { values %h }->()), $/;
print $/;

use vars qw( $a, $b, $c, $x, $y, $z );
print $a=\values %h, $/;
print $b=\values %h, $/;
print $c=\sub{values %h}->(), $/;
print $/;
print $x=\values %t, $/;
print $y=\values %t, $/;
print $z=\sub{values %t}->(), $/;

print $/;
$,= " ";
$$x= 31;
print $$x, $$y, values %t, $/;
$$y= 32;
print $$x, $$y, values %t, $/;
$$x= 33;
print $$x, $$y, values %t, $/;
__END__
Can't modify non-lvalue subroutine call at values2.pl line 6.

Can't modify non-lvalue subroutine call at values2.pl line 8.

LVALUE
SCALAR

SCALAR(0x1a7f228)
SCALAR(0x1a7f228)
SCALAR(0x1aced54)

SCALAR(0x1aced60)
SCALAR(0x1aced78)
SCALAR(0x1aced9c)

31 31 31
31 32 32
33 32 33