The Green language type system

To treat every value, including basic values (integers, chars, ...) and classes as objects increases polymorphism and makes the language easier to use. However, popular statically-typed object-oriented languages do not consider classes as first-class objects because this concept is difficult to integrate with static type checking. They also do not consider basic values as objects for sake of efficiency. This article presents the Green language type system which supports classes as classless objects and offers a mechanism to treat basic values as objects. The result is a reasonably simple type system which is statically typed, efficient, and easy to implement. It simplifies several other language mechanisms and prevents any infinite regression of metaclasses.