SICS  Intelligent Systems Laboratory

AKL, AGENTS, and Penny

AKL (AGENTS Kernel Language) is a concurrent constraint programming language developed at the Swedish Institute of Computer Science (SICS). In AKL, computation is performed by agents interacting through stores of constraints. This notion accomodates multiple programming paradigms; in appropriate contexts, AKL agents may be thought of as processes, objects, functions, relations, or constraints.

AGENTS is a system for programming in AKL. It provides a complete implementation of AKL with records, finite domain constraints (over integers), and port-based communication, a novelty of AKL. It also provides assorted built-in agents, libraries, and other support.

Penny is a parallel implementation of AKL. It utilizes both and- and or-parallelism without user annotations. The Penny system is public available for research purposes. For more information send mail to Johan Montelius (

Other AKL related activities include analysis of types and aliases in AKL programs using abstract interpretation.