Strategic Port Graph Rewriting: An Interactive Modelling and Analysis Framework

We present strategic portgraph rewriting as a basis for the implementation of visual modelling and analysis tools. The goal is to facilitate the specification, analysis and simulation of complex systems, using port graphs. A system is represented by an initial graph and a collection of graph rewriting rules, together with a user-defined strategy to control the application of rules. The strategy language includes constructs to deal with graph traversal and management of rewriting positions in the graph. We give a small-step operational semantics for the language, and describe its implementation in the graph transformation and visualisation tool PORGY.Comment: In Proceedings GRAPHITE 2014, arXiv:1407.767

Anchoring Modularity in HTML

AbstractModularity is a key feature at design, programming, proving, testing, and maintenance time, as well as a must for reusability. Most languages and systems provide built-in facilities for encapsulation, importation or parameterization. Nevertheless, there exists also languages, like HTML, with poor support for modularization. A natural idea is therefore to provide generic modularization primitives.To extend an existing language with additional and possibly formal capabilities, the notion of anchorage and Formal Island has been introduced recently. TOM for example, provides generic matching, rewriting and strategy extensions to JAVA and C.In this paper, we show on the HTML example, how to add modular features by anchoring modularization primitives in HTML. This allows one to write modular HTML descriptions, therefore facilitating their design, reusability, and maintenance, as well as providing an important step towards HTML validity checking

Termination of Rewriting with and Automated Synthesis of Forbidden Patterns

We introduce a modified version of the well-known dependency pair framework that is suitable for the termination analysis of rewriting under forbidden pattern restrictions. By attaching contexts to dependency pairs that represent the calling contexts of the corresponding recursive function calls, it is possible to incorporate the forbidden pattern restrictions in the (adapted) notion of dependency pair chains, thus yielding a sound and complete approach to termination analysis. Building upon this contextual dependency pair framework we introduce a dependency pair processor that simplifies problems by analyzing the contextual information of the dependency pairs. Moreover, we show how this processor can be used to synthesize forbidden patterns suitable for a given term rewriting system on-the-fly during the termination analysis.Comment: In Proceedings IWS 2010, arXiv:1012.533

PORGY: a Visual Analytics Platform for System Modelling and Analysis Based on Graph Rewriting

PORGY is a visual environment for rule-based modelling based on port graphs and port graph rewrite rules whose application is steered by rewriting strategies. The focus of this demonstration is the visual and interactive features offered by PORGY, which facilitate an exploratory approach to model, simu- late and analyse different ways of applying the rules while recording the model evolution, as well as tracking and plotting system parameters

Proofs in parameterized specifications

Projet EURECATheorem proving in parameterized specifications has strong connections with inductive theorem proving. An equational theorem holds in the generic theory of the parameterized specification if and only if it holds in the so-called generic algebra. Provided persistency, for any specification morphism, the translated equality holds in the initial algebra of the instantiated specification. Using a notion of generic ground reducibility, a persistency proof can be reduced to a proof of a protected enrichment. Effective tools for these proofs are studied in this paper

Rule-based programming and proving: the ELAN experience outcomes

Colloque sur invitation.Together with the Protheo team in Nancy, we have developed in the last ten years the ELAN rule-based programming language and environment. This paper presents the context and outcomes of this research effort

Termination of Rewriting with Right-Flat Rules Modulo Permutative Theories

We present decidability results for termination of classes of term rewriting systems modulo permutative theories. Termination and innermost termination modulo permutative theories are shown to be decidable for term rewrite systems (TRS) whose right-hand side terms are restricted to be shallow (variables occur at depth at most one) and linear (each variable occurs at most once). Innermost termination modulo permutative theories is also shown to be decidable for shallow TRS. We first show that a shallow TRS can be transformed into a flat (only variables and constants occur at depth one) TRS while preserving termination and innermost termination. The decidability results are then proved by showing that (a) for right-flat right-linear (flat) TRS, non-termination (respectively, innermost non-termination) implies non-termination starting from flat terms, and (b) for right-flat TRS, the existence of non-terminating derivations starting from a given term is decidable. On the negative side, we show PSPACE-hardness of termination and innermost termination for shallow right-linear TRS, and undecidability of termination for flat TRS.Comment: 20 page

Port Graphs, Rules and Strategies for Dynamic Data Analytics -Extended Abstract

International audienceIn the context of understanding, planning and anticipating the behaviour of complex systems, such as biological networks or social networks, this paper proposes port graphs, rules and strategies, combined in strategic rewrite programs, as foundational ingredients for interactive and visual programming and shows how they can contribute to dynamic data analytics

Runtime verification for biochemical programs

The biochemical paradigm is well-suited for modelling autonomous systems and new programming languages are emerging from this approach. However, in order to validate such programs, we need to define precisely their semantics and to provide verification techniques. In this paper, we consider a higher-order biochemical calculus that models the structure of system states and its dynamics thanks to rewriting abstractions, namely rules and strategies. We extend this calculus with a runtime verification technique in order to perform automatic discovery of property satisfaction failure. The property specification language is a subclass of LTL safety and liveness properties

Shematization of infinite sets of rewrite rules. Applications to the divergence of completion processes

Infinite sets of rewrite rules may be generated by completion of term rewriting systems or by a narrowing process for solving equations in equational theories. This is a severe limitation to the practical use of these processes. We propose in this paper a formalism to deal with the problem of divergence, namely the definition of melta-rules (rules with meta-variables), together with the derived notions of met-rewriting and meta-narrowing. We show how to use meta-rules for deciding the validity or satisfiability of an equation in the equational theory defined by the infinite set of rules. We define a sound and complete schematization of the infinite set of rules to ensure that the set of meta-rules and the infinite set of rules can be used equivalently