To make things faster, the memory layout matters these days. The type system is a convenient way to express memory layout. Java is a bad example, because it in

To make things faster, the memory layout matters these days. The type system is a convenient way to express memory layout. Java is a bad example, because it intentionally hides the memory layout. You could use other means than the type system, but I don't know any examples off the top of my head. Maybe some Python meta class magic?