Lygon's features include a clean declarative notion of state and the ability to express problems involving concurrency. In addition, the availability of use once predicates allows simple solutions to problems such as graph manipulation. The Mercury page at the University of Melbourne Mercury is a purely declarative logic programming language that is strongly typed and strongly moded and features a module system and determinism declarations. The Napier88 page at the University of St Andrews. Napier88 is a persistent programming language and environment with strong typing, type completeness, higher order procedures, parametric polymorphism, existential datatypes, infinite union types for system evolution, and support for graphics, distribution and concurrency.
Obliq objects have state and are local to a site.
Obliq computations can roam over the network, while maintaining network connections. The Occam Archive at Oxford. The Oz page at DFKI Oz is a concurrent constraint programming language designed for applications that require complex symbolic computations, organization into multiple agents, and soft real-time control. The Pict page at Indiana University. Pict is a concurrent programming language based on the pi-calculus.