Reversibility in the higher-order π-calculus

Abstract

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Reversibility in the higher-order π-calculus AbstractThe notion of reversible computation is attracting increasing interest because of its applications in diverse fields, in particular the study of programming abstractions for reliable systems. In this paper, we continue the study undertaken by Danos and Krivine on reversible CCS by defining a reversible higher-order π-calculus, called rhoπ. We prove that reversibility in our calculus is causally consistent and that the causal information used to support reversibility in rhoπ is consistent with the one used in the causal semantics of the π-calculus developed by Boreale and Sangiorgi. Finally, we show that one can faithfully encode rhoπ into a variant of higher-order π, substantially improving on the result we obtained in the conference version of this paper.

Reversibility in session-based concurrency: A fresh look

“…One key insight of our work is that by addressing session-based concurrency, the formal machinery required to support reversibility is simpler than in previous (untyped) reversible calculi [13,15,14,27,35] and reversible programming languages [26,36]. This simplicity is particularly evident (and convenient) in proofs of causal consistency; it emerges clearly in the kind of memory stamps that we rely on.…”

“…One limitation of the approach in [14] is that it supports CCS-like calculi, and so there is no handling of binders. Lanese et al [15,35] overcome this limitation by using memories, extending the approach of Danos and Krivine [13] in their development of the first reversible variant of the (higher-order) π-calculus. This approach has been used to give reversible semantics for programming languages [26] and more complex calculi [36].…”

“…[13]) do not consider (behavioral) types, and so their reversible semantics must account for arbitrarily complex forms of concurrent behavior. In reversing the untyped π-calculus, substitutions and scope extrusion are known to be challenging issues [27,35]. Reversing session processes is a seemingly simpler problem, as behavior is disciplined by types: once a session is established, concurrency interactions proceed in a deterministic, confluent manner.…”

Retractable and Speculative Contracts

“…The semantics defined above for retractable client/server pairs can be seen as an instantiation on contracts of the standard reversible semantics for process calculi, see, e.g., [17,29,25,26]. In particular, the semantics would become a classic uncontrolled semantics (according to the terminology in [26]) by removing the four control mechanisms below:…”

Causal-consistent rollback in a tuple-based language

“…We first present the syntax and step-by-step operational semantics of rµKlaim, then we show that this semantics satisfies the typical properties expected for a causal-consistent reversible formalism with uncontrolled reversibility, such as the ones described in [5,12,13,14,11,15]. Here, uncontrolled means that the semantics specifies how to go forward and how to go backward, but not how to choose whether to go forward or to go backward.…”