Higher order module systems, by contrast, have non trivial module manipulation facilities. Functors are functions mapping modules to modules. Programming in Modula-2. Texts and Monographs in Computer Science . Standard ML embodies today s most advanced module system.
Modules are the major structuring concept, after functions, in modern languages.
Page 53 Imperative programming. Object oriented programming. Since then various freely available implementations of Haskell have come into existence. A class declaration introduces the name of a class and the interfaces of the methods of this class. Programming in Modula-2.