my $person = MyObj->new();

# Simple string get/set
$person->name("Smith");
print $person->name();

# Define a method on the class so all instances will share it
MyObj->greeting( sub { "Hello, " . (shift)->name } );
print $person->greeting();

# Override the method for a particular instance
$person->greeting( sub { "Hi " . (shift)->name } );
print $person->greeting();

# You can change the method repeatedly with the same syntax:
$person->greeting( sub { "Hi there!" } );
print $person->greeting();