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The Green Object-Oriented Language

Green is a statically-typed object-oriented language which supports garbage collection, assertions, methods with variable number of parameters, parameterized classes, metaobjects, introspective reflection, and classes as first-class objects. The exception handling is completely object-oriented: it encapsulates exceptions and exception handling in classes, bringing all the power of object-oriented programming to the exception system. A type in Green is a collection of method signatures ― a class B is subtype of a class A if B has at least the method signatures of A, regardless B inherits from A or not. Every subclass is a subtype but not every subtype is a subclass.

Classes are objects, though classless. But they do have types and can be subtypes of normal classes. Then classes are first-class objects without the use of metaclasses. Whenever necessary, basic values such as 1, 6, ‘A’ or 3.14 are considered objects through automatic conversion to wrapper classes Integer, Char, Real, etc. This feature has been adopted recently (2004 ?) by Java. In Green, the Any class, corresponding to Object in Java or Smalltalk, can receive any type, even 1, 6 or ‘A’.

The metaobjects of Green are surprisingly efficient and easy to use, a side-effect of being designed together with the language. Green was designed almost all at once to prevent any clashes between its features so common among languages that start small and grow with the addition of unforeseen features.

See more on the home page of the Green language.