package Person; use Moose; has 'name' => (reader => '_name'); has 'age' => (reader => '_age'); sub talk { my $self = shift; printf "My name is %s and I'm %d years young\n", $self->_name, $self->_age; } package main; my $bob = Person->new(name => 'Bob', age => 55); $bob->talk(); $bob->age(1); # dies