%0 Journal Article
%T Contract-Oriented Computing in CO2
%A M. Bartoletti
%A E. Tuosto
%A R. Zunino
%J Scientific Annals of Computer Science
%D 2012
%I Alexandru Ioan Cuza University of Iasi
%X We present CO2, a parametric calculus for contract-based computing in distributed systems. By abstracting from the actual contract language, our calculus generalises both the contracts-as-processes and contracts-as-formulae paradigms. The calculus features primitives for advertising contracts, for reaching agreements, and for querying the fulfilment of contracts. Coordination among participants happens via multi-party sessions, which are created once agreements are reached. We present two instances of our calculus, by modelling contracts as processes in a variant of CCS, and as formulae in a logic. We formally relate the two paradigms, through an encoding from contracts-as-formulae to contracts-as-processes which ensures that the promises deducible in the logical system are exactly those reachable by its encoding as a process. Finally, we present a coarse-grained taxonomy of possible misbehaviours in contract-oriented systems, and we illustrate them with the help of a variety of examples.
%K contracts
%K concurrent constraint programming
%K multiparty sessions
%U http://www.infoiasi.ro/bin/download/Annals/XXII1/XXII1_1.pdf