# y $original = 'Hello.';
#my $bound-ro ::= $original;
#say $bound-ro;        # prints "Hello."
#try {
#  $bound-ro = 'Runtime error!';
#  CATCH {
#    say "$!";         # prints "Cannot modify readonly value"
#  };
#};
say $bound-ro;        # prints "Hello."
$original = 'Goodbye.';
say $bound-ro;        # prints "Goodbye."