Eiffel As a Framework for Verification
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The Essence Initiative
The Essence Initiative Ivar Jacobson Agenda Specific Problems A Case for Action - Defining a solid theoretical base - Finding a kernel of widely agreed elements Using the Kernel Final Words Being in the software development business Everyone of us knows how to develop our software, but as a community we have no widely accepted common ground A CASE FOR ACTION STATEMENT • Software engineering is gravely hampered today by immature practices. Specific problems include: – The prevalence of fads more typical of fashion industry than of an engineering discipline. – The lack of a sound, widely accepted theoretical basis. – The huge number of methods and method variants, with differences little understood and artificially magnified. – The lack of credible experimental evaluation and validation. – The split between industry practice and academic research. Agenda Specific Problems A Case for Action - Defining a solid theoretical base - Finding a kernel of widely agreed elements Using the Kernel Final Words The SEMAT initiative Software Engineering Method and Theory www.semat.org Founded by the Troika in September 2009: Ivar Jacobson – Bertrand Meyer – Richard Soley What are we going to do about it? The Grand Vision We support a process to refound software engineering based on a solid theory, proven principles and best practices The Next Steps Defining A Kernel of a solid widely agreed theoretical basis elements There are probably more than 100,000 methods Desired solution: Method Architectureincl. for instance SADT, Booch, OMT, RUP, CMMI, XP, Scrum, Lean, Kanban There are around 250 The Kernel includes identified practices incl such elements as for instance use cases, Requirement, use stories, features, Software system, components, Work, Team, Way-of- working, etc. -
Génération Automatique De Tests Unitaires Avec Praspel, Un Langage De Spécification Pour PHP the Art of Contract-Based Testing in PHP with Praspel
CORE Metadata, citation and similar papers at core.ac.uk Provided by HAL - Université de Franche-Comté G´en´erationautomatique de tests unitaires avec Praspel, un langage de sp´ecificationpour PHP Ivan Enderlin To cite this version: Ivan Enderlin. G´en´eration automatique de tests unitaires avec Praspel, un langage de sp´ecificationpour PHP. Informatique et langage [cs.CL]. Universit´ede Franche-Comt´e,2014. Fran¸cais. <NNT : 2014BESA2067>. <tel-01093355v2> HAL Id: tel-01093355 https://hal.inria.fr/tel-01093355v2 Submitted on 19 Oct 2016 HAL is a multi-disciplinary open access L'archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destin´eeau d´ep^otet `ala diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publi´esou non, lished or not. The documents may come from ´emanant des ´etablissements d'enseignement et de teaching and research institutions in France or recherche fran¸caisou ´etrangers,des laboratoires abroad, or from public or private research centers. publics ou priv´es. Thèse de Doctorat école doctorale sciences pour l’ingénieur et microtechniques UNIVERSITÉ DE FRANCHE-COMTÉ No X X X THÈSE présentée par Ivan Enderlin pour obtenir le Grade de Docteur de l’Université de Franche-Comté K 8 k Génération automatique de tests unitaires avec Praspel, un langage de spécification pour PHP The Art of Contract-based Testing in PHP with Praspel Spécialité Informatique Instituts Femto-ST (département DISC) et INRIA (laboratoire LORIA) Soutenue publiquement -
Assertions, Pre/Post- Conditions and Invariants
9/14/12 Assertions, pre/post- conditions and invariants Section 2.1 in Walls and Mirrors Section 4.5 Rosen Programming as a contract n Specifying what each method does q Specify it in a comment before method's header n Precondition q What is assumed to be true before the method is executed q Caller obligation n Postcondition q Specifies what will happen if the preconditions are met q Method obligation 1 9/14/12 Class Invariants n A class invariant is a condition that all objects of that class must satisfy while it can be observed by clients n What about Points in Cloud? q boundaries? q center? What is an assertion? n An assertion is a statement that says something about the state of your program n Should be true if there are no mistakes in the program //n == 1 while (n < limit) { n = 2 * n; } // what could you state here? 2 9/14/12 What is an assertion? n An assertion is a statement that says something about the state of your program n Should be true if there are no mistakes in the program //n == 1 while (n < limit) { n = 2 * n; } //n >= limit //more? What is an assertion? n An assertion is a statement that says something about the state of your program n Should be true if there are no mistakes in the program //n == 1 while (n < limit) { n = 2 * n; } //n >= limit //n is the smallest power of 2 >= limit 3 9/14/12 assert Using assert: assert n == 1; while (n < limit) { n = 2 * n; } assert n >= limit; When to use Assertions n We can use assertions to guarantee the behavior. -
Formal Specification Methods What Are Formal Methods? Objectives Of
ICS 221 Winter 2001 Formal Specification Methods What Are Formal Methods? ! Use of formal notations … Formal Specification Methods ! first-order logic, state machines, etc. ! … in software system descriptions … ! system models, constraints, specifications, designs, etc. David S. Rosenblum ! … for a broad range of effects … ICS 221 ! correctness, reliability, safety, security, etc. Winter 2001 ! … and varying levels of use ! guidance, documentation, rigor, mechanisms Formal method = specification language + formal reasoning Objectives of Formal Methods Why Use Formal Methods? ! Verification ! Formal methods have the potential to ! “Are we building the system right?” improve both software quality and development productivity ! Formal consistency between specificand (the thing being specified) and specification ! Circumvent problems in traditional practices ! Promote insight and understanding ! Validation ! Enhance early error detection ! “Are we building the right system?” ! Develop safe, reliable, secure software-intensive ! Testing for satisfaction of ultimate customer intent systems ! Documentation ! Facilitate verifiability of implementation ! Enable powerful analyses ! Communication among stakeholders ! simulation, animation, proof, execution, transformation ! Gain competitive advantage Why Choose Not to Use Desirable Properties of Formal Formal Methods? Specifications ! Emerging technology with unclear payoff ! Unambiguous ! Lack of experience and evidence of success ! Exactly one specificand (set) satisfies it ! Lack of automated -
Grammar-Based Testing Using Realistic Domains in PHP Ivan Enderlin, Frédéric Dadeau, Alain Giorgetti, Fabrice Bouquet
Grammar-Based Testing using Realistic Domains in PHP Ivan Enderlin, Frédéric Dadeau, Alain Giorgetti, Fabrice Bouquet To cite this version: Ivan Enderlin, Frédéric Dadeau, Alain Giorgetti, Fabrice Bouquet. Grammar-Based Testing using Realistic Domains in PHP. A-MOST 2012, 8th Workshop on Advances in Model Based Testing, joint to the ICST’12 IEEE Int. Conf. on Software Testing, Verification and Validation, Jan 2012, Canada. pp.509–518. hal-00931662 HAL Id: hal-00931662 https://hal.archives-ouvertes.fr/hal-00931662 Submitted on 16 Jan 2014 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Grammar-Based Testing using Realistic Domains in PHP Ivan Enderlin, Fred´ eric´ Dadeau, Alain Giorgetti and Fabrice Bouquet Institut FEMTO-ST UMR CNRS 6174 - University of Franche-Comte´ - INRIA CASSIS Project 16 route de Gray - 25030 Besanc¸on cedex, France Email: fivan.enderlin,frederic.dadeau,alain.giorgetti,[email protected] Abstract—This paper presents an integration of grammar- Contract-based testing [5] has been introduced in part to based testing in a framework for contract-based testing in PHP. address these limitations. It is based on the notion of Design It relies on the notion of realistic domains, that make it possible by Contract (DbC) [6] introduced by Meyer with Eiffel [7]. -
Design by Contract: the Lessons of Ariane
. Editor: Bertrand Meyer, EiffelSoft, 270 Storke Rd., Ste. 7, Goleta, CA 93117; voice (805) 685-6869; [email protected] several hours (at least in earlier versions of Ariane), it was better to let the computa- tion proceed than to stop it and then have Design by to restart it if liftoff was delayed. So the SRI computation continues for 50 seconds after the start of flight mode—well into the flight period. After takeoff, of course, this com- Contract: putation is useless. In the Ariane 5 flight, Object Technology however, it caused an exception, which was not caught and—boom. The exception was due to a floating- point error during a conversion from a 64- The Lessons bit floating-point value, representing the flight’s “horizontal bias,” to a 16-bit signed integer: In other words, the value that was converted was greater than what of Ariane can be represented as a 16-bit signed inte- ger. There was no explicit exception han- dler to catch the exception, so it followed the usual fate of uncaught exceptions and crashed the entire software, hence the onboard computers, hence the mission. This is the kind of trivial error that we Jean-Marc Jézéquel, IRISA/CNRS are all familiar with (raise your hand if you Bertrand Meyer, EiffelSoft have never done anything of this sort), although fortunately the consequences are usually less expensive. How in the world everal contributions to this made up of respected experts from major department have emphasized the European countries, which produced a How in the world could importance of design by contract report in hardly more than a month. -
Contracts for Concurrency Piotr Nienaltowski, Bertrand Meyer, Jonathan S
Contracts for concurrency Piotr Nienaltowski, Bertrand Meyer, Jonathan S. Ostroff To cite this version: Piotr Nienaltowski, Bertrand Meyer, Jonathan S. Ostroff. Contracts for concurrency. Formal Aspects of Computing, Springer Verlag, 2008, 21 (4), pp.305-318. 10.1007/s00165-007-0063-2. hal-00477897 HAL Id: hal-00477897 https://hal.archives-ouvertes.fr/hal-00477897 Submitted on 30 Apr 2010 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. DOI 10.1007/s00165-007-0063-2 BCS © 2007 Formal Aspects Formal Aspects of Computing (2009) 21: 305–318 of Computing Contracts for concurrency Piotr Nienaltowski1, Bertrand Meyer2 and Jonathan S. Ostroff3 1 Praxis High Integrity Systems Limited, 20 Manvers Street, Bath BA1 1PX, UK E-mail: [email protected] 2 ETH Zurich, Zurich, Switzerland 3 York University, Toronto, Canada Abstract. The SCOOP model extends the Eiffel programming language to provide support for concurrent programming. The model is based on the principles of Design by Contract. The semantics of contracts used in the original proposal (SCOOP 97) is not suitable for concurrent programming because it restricts parallelism and complicates reasoning about program correctness. This article outlines a new contract semantics which applies equally well in concurrent and sequential contexts and permits a flexible use of contracts for specifying the mutual rights and obligations of clients and suppliers while preserving the potential for parallelism. -
Making Sense of Agile Methods Bertrand Meyer Politecnico Di
Making sense of agile methods Bertrand Meyer Politecnico di Milano and Innopolis University Some ten years ago, I realized that I had been missing something big in software engineering. I had heard about Extreme Programming early thanks to a talk by Pete McBreen at a summer school in 1999 and another by Kent Beck himself at TOOLS USA in 2000. But I had not paid much attention to Scrum and, when I took a look, noticed two striking discrepancies in the state of agile methods. The first discrepancy was between university software engineering courses, which back then (things have changed) often did not cover agility, and the buzz in industry, which was only about agility. As I started going through the agile literature, the second discrepancy emerged: an amazing combination of the best and the worst ideas, plus much in-between. In many cases, faced with a new methodological approach, one can quickly deploy what in avionics is called Identification Friend or Foe: will it help or hurt? With agile, IFF fails. It did not help that the tone of most published discussions on agile methods (with a few exceptions, notably [1]) was adulatory. Sharing your passion for a novel approach is commendable, but not a reason to throw away your analytical skills. A precedent comes to mind: people including me who championed object-oriented programming a decade or so earlier may at times have let their enthusiasm show, but we did not fail to discuss cons along with pros. The natural reaction was to apply a rule that often helps: when curious, teach a class; when bewildered, write a book. -
Implementing Closures in Dafny Research Project Report
Implementing Closures in Dafny Research Project Report • Author: Alexandru Dima 1 • Total number of pages: 22 • Date: Tuesday 28th September, 2010 • Location: Z¨urich, Switzerland 1E-mail: [email protected] Contents 1 Introduction 1 2 Background 1 2.1 Closures . .1 2.2 Dafny . .2 3 General approach 3 4 Procedural Closures 5 4.1 Procedural Closure Type . .5 4.2 Procedural Closure Specifications . .6 4.3 A basic procedural closure example . .6 4.3.1 Discussion . .6 4.3.2 Boogie output . .8 4.4 A counter factory example . 13 4.5 Delegation example . 17 5 Pure Closures 18 5.1 Pure Closure Type . 18 5.2 A recursive while . 19 6 Conclusions 21 6.1 Limitations . 21 6.2 Possible extensions . 21 6.3 Acknowledgments . 21 2 BACKGROUND 1 Introduction Closures represent a particularly useful language feature. They provide a means to keep the functionality linked together with state, providing a source of ex- pressiveness, conciseness and, when used correctly, give programmers a sense of freedom that few other language features do. Smalltalk's standard control structures, including branches (if/then/else) and loops (while and for) are very good examples of using closures, as closures de- lay evaluation; the state they capture may be used as a private communication channel between multiple closures closed over the same environment; closures may be used for handling User Interface events; the possibilities are endless. Although they have been used for decades, static verification has not yet tack- led the problems which appear when trying to reason modularly about closures. -
Study on Eiffel
Study on Eiffel Jie Yao Anurag Katiyar May 11, 2008 Abstract This report gives an introduction to Eiffel, an object oriented language. The objective of the report is to draw the attention of the reader to the salient features of Eiffel. The report explains some of these features in brief along with language syntax. The report includes some code snippets that were written in the process of learning Eiffel. Some of the more detailed tutorials, books and papers on Eiffel can be found at www.eiffel.com 1 Contents 1 Introduction 3 2 Eiffel Constructs and Grammar 3 2.1 ”Hello World” . 3 2.2 Data Types . 3 2.3 Classes . 3 2.4 Libraries . 4 2.5 Features . 4 2.6 Class relations and hierarchy . 4 2.7 Inheritance . 4 2.8 Genericity . 5 2.9 Object Creation . 5 2.10 Exceptions . 6 2.11 Agents and Iteration . 6 2.12 Tuples . 6 2.13 Typing . 6 2.14 Scope . 7 2.15 Memory Management . 7 2.16 External software . 7 3 Fundamental Properties 7 3.1 ”Has” Properties . 8 3.2 ”Has no” Properties . 9 4 Design principles in Eiffel 10 4.1 Design by Contract . 10 4.2 Command Query Separation . 11 4.3 Uniform Access Principle . 11 4.4 Single Choice Principle . 11 5 Compilation Process in Eiffel 11 6 Exception Handling in the compiler 12 7 Garbage Collection for Eiffel 12 7.1 Garbage Collector Structure . 12 7.2 Garbage Collector in Action . 13 8 Eiffel’s approach to typing 13 8.1 Multiple inheritance . -
Verification of Object Oriented Programs Using Class Invariants
Verification of Object Oriented Programs Using Class Invariants Kees Huizing and Ruurd Kuiper and SOOP?? Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands, [email protected], [email protected] Abstract A proof system is presented for the verification and derivation of object oriented pro- grams with as main features strong typing, dynamic binding, and inheritance. The proof system is inspired on Meyer’s system of class invariants [12] and remedies its unsound- ness, which is already recognized by Meyer. Dynamic binding is treated in a flexible way: when throughout the class hierarchy overriding methods respect the pre- and post- conditions of the overridden methods, very simple proof rules for method calls suffice; more powerful proof rules are supplied for cases where one cannot or does not want to follow this restriction. The proof system is complete relative to proofs for properties of pointers and the data domain. 1 Introduction Although formal verification is not very common in the discipline of object oriented programming, the importance of formal specification is generally ac- knowledged ([12]). With the increased interest in component based develop- ment, it becomes even more important that components are specified in an un- ambiguous manner, since users or buyers of components often have no other knowledge about a component than its specification and at the same time rely heavily on its correct functioning in their framework. The specification of a class, sometimes called contract, usually contains at least pre- and postcondi- tions for the public mehtods and a class invariant. A class invariant expresses which states of the objects of the class are consis- tent, or “legal”. -
You Say 'JML' ? Wikipedia (En)
You say 'JML' ? Wikipedia (en) PDF generated using the open source mwlib toolkit. See http://code.pediapress.com/ for more information. PDF generated at: Mon, 06 Jan 2014 09:58:42 UTC Contents Articles Java Modeling Language 1 Design by contract 5 Formal methods 10 References Article Sources and Contributors 15 Image Sources, Licenses and Contributors 16 Article Licenses License 17 Java Modeling Language 1 Java Modeling Language The Java Modeling Language (JML) is a specification language for Java programs, using Hoare style pre- and postconditions and invariants, that follows the design by contract paradigm. Specifications are written as Java annotation comments to the source files, which hence can be compiled with any Java compiler. Various verification tools, such as a runtime assertion checker and the Extended Static Checker (ESC/Java) aid development. Overview JML is a behavioural interface specification language for Java modules. JML provides semantics to formally describe the behavior of a Java module, preventing ambiguity with regard to the module designers' intentions. JML inherits ideas from Eiffel, Larch and the Refinement Calculus, with the goal of providing rigorous formal semantics while still being accessible to any Java programmer. Various tools are available that make use of JML's behavioral specifications. Because specifications can be written as annotations in Java program files, or stored in separate specification files, Java modules with JML specifications can be compiled unchanged with any Java compiler. Syntax JML specifications are added to Java code in the form of annotations in comments. Java comments are interpreted as JML annotations when they begin with an @ sign.