Z meets Haskell: A case study

Z is a popular specification language which has also been used as a design tool, although much less frequently. Haskell is a programming language that was recently developed to serve as a standard for non-strict, purely functional languages. Although functional languages have proved to be excellent prototyping tools, Haskell was designed as a general purpose language which could be employed to build large applications. In this paper, we show that the formal language Z is an effective design tool when a software system is implemented in a functional language. We trace the development of a simple system from its beginning specification written in Z to its final implementation as a Haskell program. The case study is based on a specification, the class manager's assistant, found in the literature.<>