the prototype object for all kinds of numbers
| std_types::object | the prototype object for all "normal" objects |
| std_types::integer | the prototype object for all integral numbers |
| std_types::real | the prototype object for all non-integral numbers |
| std::is_a_number | obvious |
| std::ceil | default implementation for all kind of numbers |
| std::floor | default implementation for all kind of numbers |
| std::round | default implementation for all kind of numbers |