Session types as generic process types

Gay, S. J. , Gesbert, N. and Ravara, A. (2014) Session types as generic process types. Electronic Proceedings in Theoretical Computer Science, 160, pp. 94-110. (doi: 10.4204/EPTCS.160.9)

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Behavioural type systems ensure more than the usual safety guarantees of static analysis. They are based on the idea of "types-as-processes", providing dedicated type algebras for particular properties, ranging from protocol compatibility to race-freedom, lock-freedom, or even responsiveness. Two successful, although rather different, approaches, are session types and process types. The former allows to specify and verify (distributed) communication protocols using specific type (proof) systems; the latter allows to infer from a system specification a process abstraction on which it is simpler to verify properties, using a generic type (proof) system. What is the relationship between these approaches? Can the generic one subsume the specific one? At what price? And can the former be used as a compiler for the latter? The work presented herein is a step towards answers to such questions. Concretely, we define a stepwise encoding of a pi-calculus with sessions and session types (the system of Gay and Hole) into a pi-calculus with process types (the Generic Type System of Igarashi and Kobayashi). We encode session type environments, polarities (which distinguish session channels end-points), and labelled sums. We show forward and reverse operational correspondences for the encodings, as well as typing correspondences. To faithfully encode session subtyping in process types subtyping, one needs to add to the target language record constructors and new subtyping rules. In conclusion, the programming convenience of session types as protocol abstractions can be combined with the simplicity and power of the pi-calculus, taking advantage in particular of the framework provided by the Generic Type System.

Item Type:Articles
Additional Information:In Johannes Borgström and Silvia Crafa: Proceedings Combined 21st International Workshop on Expressiveness in Concurrency and 11th Workshop on Structural Operational Semantics (EXPRESS/SOS 2014), Rome, Italy, 1 September 2014
Glasgow Author(s) Enlighten ID:Gay, Professor Simon
Authors: Gay, S. J., Gesbert, N., and Ravara, A.
College/School:College of Science and Engineering > School of Computing Science
Journal Name:Electronic Proceedings in Theoretical Computer Science
Publisher:Open Publishing Association
Copyright Holders:Copyright © 2014 The Authors
First Published:First published in Electronic Proceedings in Theoretical Computer Science 160:94-110
Publisher Policy:Reproduced under a Creative Commons License
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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
612411From Data Types to Session Types - A Basis for Concurrency and Distribution.Simon GayEngineering & Physical Sciences Research Council (EPSRC)EP/K034413/1COM - COMPUTING SCIENCE