revTPL: The Reversible Temporal Process Language

TL;DR

revTPL introduces a reversible extension of the Temporal Process Language, integrating causal-consistent reversibility with discrete-time, enabling more effective debugging of concurrent systems involving time.

Contribution

It is the first to incorporate causal-consistent reversibility into a timed process algebra, bridging the gap between reversibility and real-world temporal aspects.

Findings

revTPL satisfies causal-consistent reversibility properties

It can be interpreted as an extension of reversible CCS with time

Provides a formal foundation for reversible debugging in timed concurrent systems

Abstract

Reversible debuggers help programmers to find the causes of misbehaviours in concurrent programs more quickly, by executing a program backwards from the point where a misbehaviour was observed, and looking for the bug(s) that caused it. Reversible debuggers can be founded on the well-studied theory of causal-consistent reversibility, which only allows one to undo an action provided that its consequences, if any, are undone beforehand. Causal-consistent reversibility yields more efficient debugging by reducing the number of states to be explored when looking backwards. Till now, causal-consistent reversibility has never considered time, which is a key aspect in real-world applications. Here, we study the interplay between reversibility and time in concurrent systems via a process algebra. The Temporal Process Language (TPL) by Hennessy and Regan is a well-understood extension of CCS with discrete-time and a timeout operator. We define revTPL, a reversible extension of TPL, and we show that it satisfies the properties expected from a causal-consistent reversible calculus. We show that, alternatively, revTPL can be interpreted as an extension of reversible CCS with time.