Language Design: Introduction and State of the Art

Three approaches to the design of a persistent programming language have been investigated during the FIDE₂ project. The approaches share a common assumption but differ in some basic goals. The common assumption has been that a persistent language should be statically and strongly typed, and based on a type system with parametric polymorphism, recursive types, and functions as first class values. This assumption is motivated by the fact that the reliability of code which is part of long-lived and evolving systems must be automatically checked as far as possible. Static and strong type systems are one of the most effective partial correctness checking tool currently available. On the other side, static type system can be a hindrance for evolution unless they exhibit sophisticated polymorphic features which allow changes to be accommodated.