DOCSLIB.ORG

Graph Computation Models

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Graph Computation Models Annegret Habel Mohamed Mosbah (Eds.) Graph Computation Models Second International Workshop, GCM 2008 Leicester, United Kingdom, September 2008 Proceedings Preface GCM 2008 is the second workshop of a series that serves as a forum for re- searchers that are interested in graph computation models. The scope of the workshop concerns graph computation models on graphical structures of various kinds (like graphs, diagrams, visual sentences and others). A variety of computa- tion models have been developed using graphs and graph transformations. These models include features for programming languages and systems, paradigms for software development, concurrent calculi, local computations and distributed al- gorithms, biological or chemical computations. Graph transformations can be an intermediate representation of a computation. In addition to being visual and intuitive, this representation also allows the use of mathematical methods for analysis and manipulation. The aim of the workshop is to bring together researchers interested in all aspects of computation models based on graphs and graph transformation tech- niques, and their applications. A particular emphasis is made for models and tools describing general solutions. The workshop includes tutorials and invited papers, contributed papers, and system demonstrations. The tutorials and invited papers introduce different types of graph transformations and their use to study computation models. The contributed papers consider specific topics of graph transformation models and their applications. The topics of the papers range from sequential graph transfor- mation, extended graph rewrite rules, efficient pattern matching of the left-hand side of a rule to a host graph, and the termination of a controlled graph transfor- mation system to parallel graph transformations in distributed adaptive design. The system demonstrations based on graph computation models range from alpha-versions to fully developed products that are used in education, research or being prepared for commercialisation. Accordingly, the proceedings of GCM 2008 consists of three parts. The first part comprises the extended abstracts of the tutorial and invited talks, the second part presents the contributed papers, and the third part contains extended abstracts of existing systems. We would like to thank the members of the program commitee and the secondary reviewers for their enormous help in the selection process. Moreover, we would like to express our gratitude to the local organizers Reiko Heckel (Chair) and D´enes Bisztray (Workshop chair) who did a great job. July 2008 Annegret Habel and Mohamed Mosbah Program Chairs GCM 2008 Organization GCM 2008 is organized as a satellite workshop of the 4th International Con- ference on Graph Transformation (ICGT 2008), Leicester (United Kingdom), September 7 - 13, 2008 and takes place on September 8, 2008. Program commitee Frank Drewes Umea (Sweden) Rachid Echahed IMAG, Grenoble (France) Emmanuel Godard Marseille (France) Stefan Gruner Pretoria (South Africa) Annegret Habel (Co-chair) Oldenburg (Germany) Dirk Janssens Antwerp (Belgium) Hans-J¨orgKreowski Bremen(Germany) Mohamed Mosbah (Co-chair) Bordeaux 1(France) Detlef Plump York (United Kingdom) Table of Contents Tutorial and Invited Talks Modelling computational and logistic processes by autonomous units .... 1 Hans-J¨org Kreowski From Actors to Aspects: Programming with Graph Transformations ..... 2 Dirk Jannsens An Introduction to GP ............................................ 3 Detlef Plump Local Computations in Graphs: Impact of Synchronization on Distributed Computability ......................................... 4 Jeremie Chalopin Full Papers Graph Rewrite Rules with Structural Recursion ....................... 5 Berthold Hoffmann, Edgar Jakumeit, and Rubino Geiß Assuring Strong Termination of Controlled Graph Transformation by Means of Petri Nets ............................................... 17 Renate Klempien-Hinrichs and Melanie Luderer Position Papers Efficient Graph Rewriting System Using Local Event-driven Pattern Matching ................................................... ..... 28 Bilal Said and Olivier Gasquet Editing Nested Constraints and Application Conditions ................ 35 Karl Azab Parallel Graph Transformations in Distributed Adaptive Design ......... 43 Leszek Kotulski and Barbara Strug V Systems Demonstrations Visidia: An Environment for Programming Distributed Algorithms ...... 51 Mohamed Mosbah AGG: A Tool Environment for Algebraic Graph Transformation ........ 51 Gabriele Taentzer Author Index ................................................ 52 VI Modelling computational and logistic processes by autonomous units Hans-J¨org Kreowski University of Bremen Abstract. The notion of a community of autonomous units is a graph- transformational device for the modelling of computational and - in par- ticular - logisitic processes that co-exist, run and interact in the same en- vironment. The units may communicate and cooperate with each other, their process runs may be sequential, parallel, or concurrent. In the talk, the framework will be introduced and some computational aspects stressed. From Actors to Aspects: Programming with Graph Transformations Dirk Jannsens University of Antwerp Abstract. The obvious advantage of computational models that di- rectly manipulate discrete structures or graphs is that they allow one to work on a convenient level of abstraction, close to intuition about networks, object diagrams, or system states in general, and avoiding cumbersome coding into strings or formulas. In Graph Transformation systems, one takes the view that the desired manipulations can be ob- tained though local changes, embodied by rules: not only is the applica- tion of rules controlled by pattern matching, but it is also assumed that the changes are restricted to the pattern; i.e. the part of the structure that is not involved in a rule application remains unchanged. The tutorial gives an overview of opportunities and challenges related to the use of graph transformation as a model of computation. As a starting point, work concerning Actor languages is used, which is based on very simple mathematics and should hence be accessible to a public not acquainted with the existing theory of graph transformation. Then issues concerning concurrency and modularity are discussed, as well as the challenges caused by the need to introduce more control and generic- ity than present in the basic mechanism. Finally we discuss how proposed solutions to these challenges are used in recent work about refactoring and model transformation, and we outline some further potential appli- cations to aspect-oriented or delegation-based languages, as well as to topics outside of traditional computing science, such as self-assembly or natural computing. An Introduction to GP Detlef Plump The University of York Abstract. GP is a rule-based, nondeterministic programming language for solving graph problems at a high level of abstraction, freeing pro- grammers from dealing with low-level data structures. GP’s design aims at syntactic and semantic simplicity, to facilitate formal reasoning about programs. The language core consists of just four constructs: single-step application of a set of graph-transformation rules, sequential composi- tion, branching and looping. This talk introduces GP by a number of example programs, presents a formal semantics in the style of Plotkin’s structural operational semantics, and briefly describes the current imple- mentation. Particular attention will be given to GP’s powerful branching and looping constructs which allow to hide destructive tests and to iter- ate arbitrary subprograms. Local Computations in Graphs: Impact of Synchronization on Distributed Computability Jeremie Chalopin University of Marseille Abstract. In this talk, I will present different distributed models that can be expressed by graph relabelling systems. In these models, a com- putation step can be described by the application of a local relabelling rule that enables the modification of the states of neighboring vertices. These models represent different level of synchronization between adja- cent processes. We are interested in the computational power of these different models. In order to highlight the differences between these models, we study two classical problems in distributed computing: naming and election. The study of these problems enables to give a hierarchy between the different models and it enables to understand what kind of results are general enough to be expressed in each model. Graph Rewrite Rules with Structural Recursion Berthold Hoffmann1, Edgar Jakumeit2, and Rubino Geiß2 3 1 Universit¨at Bremen and DFKI-Lab Bremen, Germany 2 Universit¨at Karlsruhe (TH), Germany 3 LPA GmbH Frankfurt/Main, Germany Abstract. Graph rewrite rules, programmed by sequencing and itera- tion, suffice to define the computable functions on graphs—in theory. In practice however, the control program may become hard to formulate, hard to understand, and even harder to verify. Therefore, we have ex- tended graph rewrite rules by variables that are instantiated by a kind of hyperedge replacement, before the so instantiated rules are applied to a graph. This way, rules can be defined recursively over the structure of the graphs where they apply, in a fully declarative way. Generic rules with variables and recursive rule instantiation have been implemented in the graph rewrite tool GrGen. 1 Introduction Graph rewriting is a basis for rule-based
Load more

Recommended publications
  • Adding Change Impact Analysis to the Formal Verification of C Programs
    Adding Change Impact Analysis to the Formal Verification of C Programs Serge Autexier and Christoph Lüth? Deutsches Forschungszentrum für Künstliche Intelligenz (DFKI), Enrique-Schmidt-Str. 5, 28359 Bremen, Germany [email protected], [email protected] Abstract. Handling changes to programs and specifications efficiently is a particular challenge in formal software verification. Change impact analysis is an approach to this challenge where the effects of changes made to a document (such as a program or specification) are described in terms of rules on a semantic representation of the document. This allows to describe and delimit the effects of syntactic changes semantically. This paper presents an application of generic change impact analysis to formal software verification, using the GMoC and SAMS tools. We adapt the GMoC tool for generic change impact analysis to the SAMS verification framework for the formal verification of C programs, and show how a few simple rules are sufficient to capture the essence of change management. 1 Introduction Software verification has come of age, and a lot of viable approaches to verifying the correctness of an implementation with respect to a given specification exist. However, the real challenge in software verification is to cope with changes — real software is never finished, the requirements may change, the implementa- tion may change, or the underlying hardware may change (particularly in the embedded domain, where hardware is a major cost factor). Here, many existing approaches show weaknesses; it is not untypical to handle changes by rerunning the verification and see where it fails (though there exist more sophisticated approaches [1, 5], cf.
    [Show full text]
  • The Grgen User Manual
    Universit¨atKarlsruhe (TH) Forschungsuniversit¨at · gegr¨undet1825 Fakult¨atf¨urInformatik Institut f¨urProgrammstrukturen und Datenorganisation Lehrstuhl Prof. Goos The GrGen.NET User Manual Refers to GrGen.NET Release 2.7 milestone 1 |DRAFT| www.grgen.net Jakob Blomer Rubino Geiß Edgar Jakumeit December 5, 2010 ii ABSTRACT GrGen.NET: transformation of structures made easy { with languages for graph modeling, pattern matching, and rewrit- ing, as well as rule control; brought to life by a compiler and a rapid prototyping environment offering graphical and step- wise debugging. The Graph Rewrite Generator is a tool en- abling elegant and convenient development of graph rewriting applications with comparable performance to conventionally developed ones. This user manual contains both, normative statements in the sense of a reference manual as well as an informal guide to the features and usage of GrGen.NET. This manual is licensed under the terms of the Creative Commons Attribution-Share Alike 3.0 Germany license. The license is available at http://creativecommons.org/licenses/by-sa/3.0/de/ iii iv FOREWORD FOR RELEASE 1.4 First of all a word about the term \graph rewriting". Some would rather say \graph trans- formation"; some even think there is a difference between these two. We don't see such differences and use graph rewriting for consistency. The GrGen project started in spring 2003 with the diploma thesis of Sebastian Hack un- der supervision of Rubino Geiß. At that time we needed a tool to find patterns in graph based intermediate representations used in compiler construction. We imagined a tool that is fast, expressive, and easy to integrate into our compiler infrastructure.
    [Show full text]
  • Foundational Analysis Techniques for High-Level Transformation Programs
    Foundational Analysis Techniques for High-Level Transformation Programs Ahmad Salim Al-Sibahi Advisors: Committee: Andrzej Wąsowski Riko Jacob, IT University of Copenhagen Aleksandar Dimovski Tijs van der Storm, University of Groningen Submitted: September 2017 Xavier Rival, CNRS/ENS/INRIA/PSL Research University A A yst dqÌt Hy wkyF A w rysA rb yl rb Progress is beyond improving what is; Progress is moving towards what will be. Gibran Khalil Gibran v Abstract High-level transformation languages like TXL and Rascal, sim- plify writing and maintaining transformations such as refactorings and optimizations, by providing specialized language constructs that include powerful pattern matching, generic traversals, and fixed-point iteration. This expressivity unfortunately makes it hard to reason about the semantics of these languages, and there ex- ists few automated validation and verification tools for these lan- guages. The goal of this dissertation is to develop foundational tech- niques and prototype tools for verifying transformation programs, based on techniques from traditional programming language re- search. At first, I present a systematic analysis of declarative high- level transformation languages, like QVT and ATL, seeking to clar- ify their expressiveness. The analysis showed that virtually all ex- amined languages were Turing-complete and thus could not be treated specially for verification. I describe a joint effort in designing and validating an indus- trial modernization project using the high-level transformation lan- guage TXL. The transformation was validated using the translation validation and symbolic execution, catching 50 serious bug cases in an otherwise well-tested expert-written transformation, and thus showing the need for verification tools in this domain.
    [Show full text]
  • Foundational Analysis Techniques for High-Level Transformation Programs
    Foundational Analysis Techniques for High-Level Transformation Programs Ahmad Salim Al-Sibahi Advisors: Committee: Andrzej Wąsowski Riko Jacob, IT University of Copenhagen Aleksandar Dimovski Tijs van der Storm, University of Groningen Submitted: September 2017 Xavier Rival, CNRS/ENS/INRIA/PSL Research University A A yst dqÌt Hy wkyF A w rysA rb yl rb Progress is beyond improving what is; Progress is moving towards what will be. Gibran Khalil Gibran v Abstract High-level transformation languages like TXL and Rascal, simplify writing and maintaining transformations such as refactorings and optimizations, by providing specialized language constructs that include powerful pattern matching, generic traversals, and fixed- point iteration. This expressivity unfortunately makes it hard to reason about the semantics of these languages, and there exists few automated validation and verification tools for these languages. The goal of this dissertation is to develop foundational tech- niques and prototype tools for verifying transformation programs, based on techniques from traditional programming language re- search. At first, I present a systematic analysis of declarative high- level transformation languages, like QVT and ATL, seeking to clar- ify their expressiveness. The analysis showed that virtually all ex- amined languages were Turing-complete and thus could not be treated specially for verification. I describe a joint effort in designing and validating an indus- trial modernization project using the high-level transformation lan- guage TXL. The transformation was validated using the translation validation and symbolic execution, catching 50 serious bug cases in an otherwise well-tested expert-written transformation, and thus showing the need for verification tools in this domain.
    [Show full text]
  • Domain Specific Language Tool Development
    University of Latvia ELĪNA KALNIŅA MODEL TRANSFORMATION DEVELOPMENT USING MOLA MAPPINGS AND TEMPLATE MOLA Thesis for the PhD Degree at the University of Latvia Field: Computer Science Section: Programming Languages and Systems Scientific Advisor: Prof., Dr. Habil. Sc. Comp. AUDRIS KALNINS Riga – 2011 This work has been supported by the European Social Fund within the project «Support for Doctoral Studies at University of Latvia». Scientific Advisor: Professor, Dr. Sc. Comp. Audris Kalniņš Latvijas Universitāte Referees: Professor, Dr. Sc. Comp. Guntis Bārzdiņš University of Latvia Professor, Dr. Sc. Ing. Oksana Ņikiforova Riga Technical University Professor, Dr. Olegas Vasilecas Vilnius Gediminas Technical University (Vilnius, Lithuania) The defence of the thesis will take place in an open session of the Council of Promotion in Computer Science of the University of Latvia, in the Institute of Mathematics and Computer Science of the University of Latvia (Room 413, Raina Boulevard 29, Riga, Latvia) on March 7, 2012 at 4 PM. The thesis and its summary are available at the library of the University of Latvia (Kalpaka Boulevard 4, Riga, Latvia). 3 4 ABSTRACT Model transformation development for three specific domains: Model-Driven Software Development (MDSD), DSL tool development and transformation synthesis has been studied in the thesis. It is concluded that transformation development in domain- specific transformation languages is more straightforward and faster compared to traditional transformation languages. A domain-specific model transformation language has been developed for each studied domain. Two of them are based on mappings. In both cases it was concluded that mappings better fit for typical tasks and transformations better fit for non-standard tasks.
    [Show full text]
  • Solving the TTC 2014 Movie Database Case with Grgen.NET
    Solving the TTC 2014 Movie Database Case with GrGen.NET Edgar Jakumeit [email protected] The task of the Movie Database Case [2] is to identify all couples of actors who performed together in at least three movies. The challenge of the task is to do this fast on a large database. We employ the general purpose graph rewrite system GRGEN.NET in developing and optimizing a solution. 1 What is GrGen.NET? GRGEN.NET (www.grgen.net) is a programming language and development tool for graph structured data with pattern matching and rewriting at its core, which furthermore supports imperative and object- oriented programming, and features some traits of database-like query-result processing. Founded on a rich data modeling language with multiple inheritance on node and edge types, it offers pattern-based rewrite rules of very high expressiveness, with subpatterns and nested alternative, iterated, negative, and independent patterns, as well as preset input parameters and output def variables yielded to. The rules are orchestrated with a concise control language, which offers constructs that are simplifying backtracking searches and state space enumerations. Development is supported by graphical and stepwise debugging, as well as search plan explanation and profiling instrumentation for graph search steps – the former helps in first getting the programs correct, the latter in getting them fast thereafter. The tool was built for performance and scalability: its model data structures are designed for fast processing of typed graphs at modest memory consumption, while its optimizing compiler adapts the search process to the characteristics of the host graph at hand and removes overhead where it is not needed.
    [Show full text]
  • GP 2: Efficient Implementation of a Graph Programming Language
    GP 2: Efficient Implementation of a Graph Programming Language Christopher Bak Doctor of Philosophy University of York Computer Science September 2015 2 Abstract The graph programming language GP (Graph Programs) 2 and its implemen- tation is the subject of this thesis. The language allows programmers to write visual graph programs at a high level of abstraction, bringing the task of solving graph-based problems to an environment in which the user feels comfortable and secure. Implementing graph programs presents two main challenges. The first challenge is translating programs from a high-level source code representation to executable code, which involves bridging the gap from a non-deterministic pro- gram to deterministic machine code. The second challenge is overcoming the theoretically impractical complexity of applying graph transformation rules, the basic computation step of a graph program. The work presented in this thesis addresses both of these challenges. We tackle the first challenge by implementing a compiler that translates GP 2 graph pro- grams directly to C code. Implementation strategies concerning the storage and access of internal data structures are empirically compared to determine the most efficient approach for executing practical graph programs. The second challenge is met by extending the double-pushout approach to graph transformation with root nodes to support fast execution of graph transformation rules by restricting the search to the local neighbourhood of the root nodes in the host graph. We add this theoretical construct to the GP 2 language in order to support rooted graph transformation rules, and we identify a class of rooted rules that are appli- cable in constant time on certain classes of graphs.
    [Show full text]
  • Using Internal Domain-Specific Languages to Inherit Tool Support
    Journal of Software & Systems Modelling manuscript No. (will be inserted by the editor) Using Internal Domain-Specific Languages to inherit Tool Support and Modularity for Model Transformations Georg Hinkel · Thomas Goldschmidt · Erik Burger · Ralf Reussner Received: March 14, 2016 / Revision: January 5, 2017/ Accepted: not yet Abstract Model-driven engineering (MDE) has pro- .NET platform. The results confirm the value of inher- ven to be a useful approach to cope with todays ever ited modularity and tool support while conciseness and growing complexity in the development of software sys- understandability are still competitive. tems; nevertheless, it is not widely applied in industry. Keywords Model-driven Engineering · Model Trans- As suggested by multiple studies, tool support is a ma- formation · Domain-Specific Language · Tool Support · jor factor for this lack of adoption. Especially the devel- Extensibility opment of model transformations lacks good tool sup- port. Additionally, modularization techniques are in- evitable for the development of larger model transfor- 1 Introduction mations to keep them maintainable. Existing tools for MDE, in particular model transformation approaches, The increasing complexity of software systems has been are often developed by small teams and cannot keep tackled in the past by increasing the abstraction of pro- up with advanced tool support for mainstream gen- gramming languages. Today, it seems as if the abstrac- eral purpose programming languages, such as IntelliJ tion level of modern programming languages can hardly or Visual Studio. Internal DSLs are a promising solu- be raised without losing general purpose applicability. tion to these problems. In this paper, we investigate In recent years, many domain-specific languages (DSLs) the impact of design decisions of an internal DSL to the [10] have been proposed, which can be used to describe reuse of tool support and modularization concepts from systems at a higher abstraction level in terms of domain the host language.
    [Show full text]
  • Object-Oriented Graph Grammars for Computational Design Synthesis
    TECHNISCHE UNIVERSITÄT MÜNCHEN Lehrstuhl für Produktentwicklung Object-Oriented Graph Grammars for Computational Design Synthesis Bergen Helms Vollständiger Abdruck der von der Fakultät für Maschinenwesen der Technischen Universität München zur Erlangung des akademischen Grades eines Doktor-Ingenieurs genehmigten Dissertation. Vorsitzender: Univ.-Prof. Dr. rer. nat. Dr. h.c. Ulrich Walter Prüfer der Dissertation: 1. Univ.-Prof. Kristina Shea, Ph.D., Eidgenössische Technische Hochschule Zürich, Schweiz 2. Univ.-Prof. Dr.-Ing. Martin Eigner, Technische Universität Kaiserlsautern 3. Univ.-Prof. Dr.-Ing. Udo Lindemann Die Dissertation wurde am 20.09.2012 bei der Technischen Universität München eingereicht und durch die Fakultät für Maschinenwesen am 06.02.2013 angenommen. Abstract Conceptual design is an early design phase that is acknowledged as particularly critical. Its goal is the determination of the product’s essential characteristics that meet the given requirements. Conceptual design is characterized by high uncertainty resulting from lacking knowledge about the future prod- uct that makes it difficult to evaluate design quality and to systematically explore the set of solutions. Computational Design Synthesis (CDS) aims at supporting conceptual design through formalization and automation of knowledge-intensive design tasks. However, CDS still has little acceptance in industry due to the high effort required for knowledge and task formalization, the limited scope of application, the lack of reuse of existing paper-based design knowledge, the lack of modeling standards and tool integration, and the low maturity of software tools. The potential of CDS to increase development efficiency and innovative power motivates addressing these problems. This thesis contributes to the goal of increasing the applicability of CDS in every day design practice with the development and implementation of a hy- brid knowledge representation, termed object-oriented graph grammar, and an approach to automatically formalize engineering knowledge from design catalogs.
    [Show full text]
  • Paisley: a Pattern Matching Library for Arbitrary Object Models
    Paisley: APatternMatching Library forArbitrary Object Models Baltasar Trancon´ yWidemann Markus Lepper Technische Universitat¨ Ilmenau <semantics/> GmbH b-alutcaisarn.tnn.ol@ra tmau De e Abstract: Professional development of software dealing with structured models re- quires more systematic approach and semantic foundation than standard practice in general-purpose programming languages affords. One remedy is to integrate tech- niques from other programming paradigms, as seamless as possible and without forc- ing programmers to leave their comfort zone. Here we present atool for the imple- mentation of pattern matching as fundamental means of automated data extraction from models of arbitrary shape and complexity in ageneral-purpose programming language. The interface is simple but, thanks to elaborate and rigorous design, is also light-weight, portable, non-invasive,type-safe, modular and extensible. It is compat- ible with object-oriented data abstraction and has full support for nondeterminism by backtracking. The tool comes as alibrary consisting of twolevels: elementary pat- tern algebra (generic, highly reusable) and pattern bindings for particular data models (specific, fairly reusable, user-definable). Applications use the library code in asmall number of idiomatic ways, making pattern-matching code declarative in style, easily writable, readable and maintainable. Library and idiom together form atightly em- bedded domain-specific language; no extension of the host language is required. The current implementation is in Java,but assumes only standard object-oriented features, and can hence be ported to other mainstream languages. 1Introduction Declarative (functional or logical) languages are more or less equally powerful both when creating compound data, and when extracting their components: Term/pattern constructors on the right/left hand side of definition equations, respectively,offer balanced syntactic support with clean, inverse algebraic semantics.
    [Show full text]
  • Object-Oriented Concepts for Computational Design Synthesis
    INTERNATIONAL DESIGN CONFERENCE - DESIGN 2010 Dubrovnik - Croatia, May 17 - 20, 2010. OBJECT-ORIENTED CONCEPTS FOR COMPUTATIONAL DESIGN SYNTHESIS B. Helms and K. Shea Keywords: computational design synthesis, graph grammars, object- oriented programming, implementation 1. Introduction Computational tools have become routine means of support in the development of new, innovative and complex products in the last decades. The aim of approaches and tools in the area of computational design synthesis are to generate alternative solutions tailored to particular problems and to computationally describe solution spaces. As not only products are getting more and more complex, but also the environments in which they are developed and used, research in the field has proven it’s capability to support engineers when dealing with these challenges. However, design synthesis tools need to extend their scope of applications and become more efficient, more intelligent and more flexible in order to encourage industry up-take. A similar situation led in the sixties – after procedural programming has proven its great potential – to the development of the concepts of object-orientation and their implementation in the programming language Simula-67 [Meyer 1997]. This paper presents goals and concepts from object-oriented programming, points out their benefits and draws analogies to computational design synthesis in order to seize the same or similar benefits. More specifically, the realization of object-oriented techniques in design synthesis is presented in the context of graph-grammars. The aim of this paper is to present how the fundamentals of object-orientation are applicable in the computational design synthesis methodology and open the field for new promising applications.
    [Show full text]
  • From Imperative to Rule-Based Graph Programs (Extended Abstract)
    From Imperative to Rule-based Graph Programs (Extended Abstract) Detlef Plump The University of York, UK 1 Introduction The use of graphs to model dynamic structures is ubiquitous in computer science; prominent example areas include compiler construction, pointer programming, natural language processing, and model-driven software development. The behaviour of systems in such areas can be naturally captured by graph transformation rules specifying small state changes. Domain-specific languages based on graph transformation rules include Groove [4], GrGen.Net [5] and Porgy [3]. This paper focusses on the graph programming language GP [6, 7] which aims to support formal reasoning on programs (see [8] for a Hoare-logic approach to verifying GP programs). We discuss the translation of (the core of) a simple imperative programming language to GP. The motivation for this is threefold: 1. To prove that GP is computationally complete, in the strong sense that graph functions are computable if and only if they can be directly computed with GP programs. 2. To identify a complete sublanguage of GP, by restricting as much as possible the form of rules and control constructs in the target language. 3. To demonstrate in principle that imperative languages based on registers and assignments can be smoothly translated to a language based on graph transformation rules and pattern matching. We use high-level random access machines (HRAMs) as a prototypical imperative language. They differ from standard RAMs in that they operate on registers holding lists of integers and use while loops and if-then-else commands. HRAM commands are translated into equivalent GP commands working on graphs that consist of register-like nodes.
    [Show full text]