print q(Testing FETCH error for undefined value,), $/; 
defined( eval { print 'foo is ', foo, $/ }) or print $@, $/;

print q(Testing STORE error for invalid value, 'quasi',), $/;
print defined( eval { foo = 'quasi'}) ?
      ('foo is ', foo, $/, $/) :
      ($@, $/);

print q(Testing STORE error valid value, 'quash',), $/;
print defined( eval { foo = 'quash'}) ?
      ('foo is ', foo, $/, $/) :
      ($@, $/);

print q(Testing modification, 'foo =~ s/h/e/',), $/;
print defined( eval { foo =~ s/h/e/}) ?
      ('foo is ', foo, ' - ERROR', $/, $/) :
      ($@, $/);

print q(Testing TIESCALAR error invalid value, 'suite',), $/;
print defined( eval {
          tie my $bar, 'Constrained',
              sub {shift=~/^$c$v$v$c$c$/}, 'suite';
          sub bar () :lvalue { $bar }
      }) ?
      ('bar is ', bar, $/, $/) :
      ($@, $/);

print q(Testing TIESCALAR error valid value, 'suits',), $/;
print defined( eval {
          tie my $baz, 'Constrained',
              sub {shift=~/^$c$v$v$c$c$/}, 'suits';
          sub baz () :lvalue { $baz }
      }) ?
      ('baz is ', baz, $/, $/) :
      ($@, $/);