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Abstract : |
We develop a general semantic theory of asynchronous communication in concurrent logic and concurrent constraint languages. The main characteristic of these languages, from the point of view of the communication mechanism, is that processes interact by querying and updating some common data structure. We abstract from the specific features of the underlying data structure by means of a uniform language of which the actions are interpreted as transformations on an abstract set of states. This approach shows that there exists a basic similarity between concurrent logic (constraint) languages and other languages based on asynchrononous communication, like dataflow and asynchronous CSP. Actually, our intention is to capture languages based on asynchronous communication as instances of this uniform language, such an instance being determined by a specific set of states and interpretation of the actions. The computational model of our paradigm is described by a transition system in the style of Plotkin's SOS. A compositional model is presented that is based on reactive sequences, i.e., sequences of pairs of states. 1, |
