Executable Structural Operational Semantics in Maude

This paper describes in detail how to bridge the gap between theory and practice when implementing in Maude structural operational semantics described in rewriting logic, where transitions become rewrites and inference rules become conditional rewrite rules with rewrites in the conditions, as made possible by the new features in Maude 2.0. We validate this technique using it in several case studies: a functional language Fpl (evaluation and computation semantics, including an abstract machine), imperative languages WhileL (evaluation and computation semantics) and GuardL with nondeterminism (computation semantics), Kahn’s functional language Mini-ML (evaluation or natural semantics), Milner’s CCS (with strong and weak transitions), and Full LOTOS (including ACT ONE data type specifications). In addition, on top of CCS we develop an implementation of the Hennessy-Milner modal logic for describing local capabilities of processes, and for LOTOS we build an entire tool where Full LOTOS specifications can be entered and executed (without user knowledge of the underlying implementation of the semantics). We also compare this method based on transitions as rewrites with another one based on transitions as judgements

Alternating bit protocol as an example of compositional system specification

We show a complete modular specification of the alternating bit protocol. We use the syntax of Maude extended with our constructs for the synchronous composition. Also, we make intensive use of parameterized programming to encapsulate components and specify interfaces. This paper must be considered a companion to some of our previous ones

Modular specification in rewriting logic (extended version)

Our aim is to bring modularity to system specification in rewriting logic. Modularity here is in the sense of decomposing a system into its functional components, coding the specification for each component as a separate system, and then assembling them back. Rewriting logic is well suited for the specification of concurrent and non-deterministic systems but, up to now, modularity could hardly be addressed within it. The base of our proposal is the operation that we call synchronous composition. We discuss the reasons and implications of our proposal, and formalize it for rewriting logic and also for transition structures, to be used as semantics. To show the power of our approach, we include a few small but realistic examples and a larger example on cached computer architecture

Two Decades of Maude

This paper is a tribute to José Meseguer, from the rest of us in the Maude team, reviewing the past, the present, and the future of the language and system with which we have been working for around two decades under his leadership. After reviewing the origins and the language's main features, we present the latest additions to the language and some features currently under development. This paper is not an introduction to Maude, and some familiarity with it and with rewriting logic are indeed assumed.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

A Declarative Debugger for Maude Specifications: User Guide

We show in this guide how to use our declarative debugger for Maude specifications. Declarative debugging is a semi-automatic technique that starts from a computation considered incorrect by the user (error symptom) and locates a program fragment responsible for the error by asking questions to an external oracle, which is usually the user. In our case the debugging tree is obtained from a proof tree in a suitable semantic calculus; more concretely, we abbreviate the proof trees obtained from this calculus in order to ease and shorten the debugging process while preserving the correctness and completeness of the technique. We present the main features of our tool, what is assumed about the modules introduced by the user, the list of available commands, and the kinds of questions used during the debugging process. Then, we use several examples to illustrate how to use the debugger. We refer the interested reader to the webpage http://maude.sip.ucm.es/debugging, where these and other examples can be found together with more information about the theory underlying the debugger, its implementation and the Maude source files