The 14th Overture Workshop: Towards Analytical Tool Chains

This report contains the proceedings from the 14th Overture workshop organized in connection with the Formal Methods 2016 symposium. This includes nine papers describing different technological progress in relation to the Overture/VDM tool support and its connection with other tools such as Crescendo, Symphony, INTO-CPS, TASTE and ViennaTalk

Implementing a smalltalk to Java translator

A number of essential issues in translating Smalltalk to Java are addressed. The fIrst chapter gives a brief overview of Smalltalk and Java with respect to the relevant language features that will be translated. In the next section a convention is proposed for mapping Smalltalk method selectors to Java method names. The dynamic nature of Smalltalk instance methods is compared with Java's static type model as well as a solution to simulate the dynamic nature of Smalltalk in Java. A Java class hierarchy that parallels the Smalltalk class hierarchy (including the metaclass objects) is suggested. A further proposal is given for translating the dynamic attributes of Smalltalk class methods to the same behaviour to Java. These proposals are used to support ways of mapping both Smalltalk instance methods, as well as Smalltalk class methods to their Java counterparts. Ways of translating Smalltalk class variables, Smalltalk class instance variables and Smalltalk global variables are illustrated. A method for translating Smalltalk blocks to Java inner classes is implemented using Java exceptions to unwind the call stack. Various types of Small talk blocks are translated with increasing complexity. The various types of blocks translated are simple blocks; blocks with references to variables in the enclosing context; blocks with block arguments; blocks that need to refer to their own context executed from other contexts; blocks with multiple exit points as well as nested blocks. Some performance tests to illustrate the impact of using exceptions in Java are also reported. The next section introduces the Small talk grammar with the necessary productions used to implement a parser. Lexical and syntax analysis are explained. A brief overview of a recursive descent parser is given where an example of Smalltalk source code is parsed and all the relevant parse nodes illustrated. The encoding in each parse node to Java source is shown. The last section focuses on similar initiatives being pursued and compares the solutions in the dissertation against them. This dissertation focuses on key areas of the Smalltalk to Java translation process, but a few peculiar and unique Smalltalk features are not addressed. These are discussed in the last section and some suggestions are made on how the translations can be achieved.Dissertation (MSc (Computer Science))--University of Pretoria, 2006.Computer Scienceunrestricte

Approaches to Interpreter Composition

In this paper, we compose six different Python and Prolog VMs into 4 pairwise compositions: one using C interpreters; one running on the JVM; one using meta-tracing interpreters; and one using a C interpreter and a meta-tracing interpreter. We show that programs that cross the language barrier frequently execute faster in a meta-tracing composition, and that meta-tracing imposes a significantly lower overhead on composed programs relative to mono-language programs.Comment: 33 pages, 1 figure, 9 table

Programming Language Feature Agglomeration

Feature-creep is a well-known phenomenon in software systems. In this paper, we argue that feature-creep also occurs in the domain of programming languages. Recent languages are more expressive than earlier languages. However recent languages generally extend rather than replace the syntax (sometimes) and semantics (almost always) of earlier languages. We demonstrate this trend of agglomeration in a sequence of languages comprising Pascal, C, Java, and Scala. These are all block-structured Algol-derived languages, with earlier languages providing explicit inspiration for later ones. We present empirical evidence from several language-specific sources, including grammar definitions and canonical manuals. The evidence suggests that there is a trend of increasing complexity in modern languages that have evolved from earlier languages

AtomSim: web-deployed atomistic dynamics simulator

AtomSim, a collection of interfaces for computational crystallography simulations, has been developed. It uses forcefield-based dynamics through physics engines such as the General Utility Lattice Program, and can be integrated into larger computational frameworks such as the Virtual Neutron Facility for processing its dynamics into scattering functions, dynamical functions etc. It is also available as a Google App Engine-hosted web-deployed interface. Examples of a quartz molecular dynamics run and a hafnium dioxide phonon calculation are presented

How to Find Suitable Ontologies Using an Ontology-based WWW Broker

Knowledge reuse by means of outologies now faces three important problems: (1) there are no standardized identifying features that characterize ontologies from the user point of view; (2) there are no web sites using the same logical organization, presenting relevant information about ontologies; and (3) the search for appropriate ontologies is hard, time-consuming and usually fruitless. To solve the above problems, we present: (1) a living set of features that allow us to characterize ontologies from the user point of view and have the same logical organization; (2) a living domain ontology about ontologies (called ReferenceOntology) that gathers, describes and has links to existing ontologies; and (3) (ONTO)2Agent, the ontology-based www broker about ontologies that uses the Reference Ontology as a source of its knowledge and retrieves descriptions of ontologies that satisfy a given set of constraints. (ONTO)~Agent is available at http://delicias.dia.fi.upm.es/REFERENCE ONTOLOGY

KafKa: Gradual Typing for Objects

A wide range of gradual type systems have been proposed, providing many languages with the ability to mix typed and untyped code. However, hiding under language details, these gradual type systems embody fundamentally different ideas of what it means to be well-typed. In this paper, we show that four of the most common gradual type systems provide distinct guarantees, and we give a formal framework for comparing gradual type systems for object-oriented languages. First, we show that the different gradual type systems are practically distinguishable via a three-part litmus test. We present a formal framework for defining and comparing gradual type systems. Within this framework, different gradual type systems become translations between a common source and target language, allowing for direct comparison of semantics and guarantees

A Pure Java Parallel Flow Solver

In this paper an overview is given on the "Have Java" project to attain a pure Java parallel Navier-Stokes flow solver (JParNSS) based on the thread concept and remote method invocation (RMI). The goal of this project is to produce an industrial flow solver running on an arbitrary sequential or parallel architecture, utilizing the Internet, capable of handling the most complex 3D geometries as well as flow physics, and also linking to codes in other areas such as aeroelasticity etc. Since Java is completely object-oriented the code has been written in an object-oriented programming (OOP) style. The code also includes a graphics user interface (GUI) as well as an interactive steering package for the parallel architecture. The Java OOP approach provides profoundly improved software productivity, robustness, and security as well as reusability and maintainability. OOP allows code construction similar to the aerodynamic design process because objects can be software coded and integrated, reflecting actual design procedures. In addition, Java is the programming language of the Internet and thus Java is the programming language of the Internet and thus Java objects on disparate machines or even separate networks can be connected. We explain the motivation for the design of JParNSS along with its capabilities that set it apart from other solvers. In the first two sections we present a discussion of the Java language as the programming tool for aerospace applications. In section three the objectives of the Have Java project are presented. In the next section the layer structures of JParNSS are discussed with emphasis on the parallelization and client-server (RMI) layers. JParNSS, like its predecessor ParNSS (ANSI-C), is based on the multiblock idea, and allows for arbitrarily complex topologies. Grids are accepted in GridPro property settings, grids of any size or block number can be directly read by JParNSS without any further modifications, requiring no additional preparation time for the solver input. In the last section, computational results are presented, with emphasis on multiprocessor Pentium and Sun parallel systems run by the Solaris operating system (OS)

Automatic conversion of ADA source code to scala

Tese de mestrado, Engenharia Informática (Arquitetura, Sistemas e Redes de Computadores) Universidade de Lisboa, Faculdade de Ciências, 2020When the popularity of a programming language declines, there are often sizeable existing legacy codebases that need to be modernized. However, migrating off of these legacy languages is very costly. In addition, these declining languages do not necessarily have the same feature set as a modern language. As such, there are often specific features only present in the legacy language, which are useful for a variety of applications, making it hard for modern languages to penetrate these domains. This thesis presents a study of how these advanced features in legacy programming languages can be implemented in modern languages. As a use case, we will consider Ada, a language which is declining in popularity, and we evaluate which modern languages can adequately express Ada’s features. We select Scala as the most suitable language, due to its advanced type system, macro capabilities, implicit functions and constructors, and operator overloading. In addition, we present a set of translation rules from Ada to Scala, which was implemented in an automatic translation tool. Previous work on this domain tends to focus either on semantic correctness or on readability, eschewing one for the other, rather than tackling both at the same time. However, by carefully picking a target language with enough features that lend themselves for this kind of translation, we achieve a result that preserves both semantics and similarity, while maintaining an acceptable level of readability. We expect that this result to reduce the time and monetary cost of migrating off these legacy platforms, thereby making automated conversion of large software systems more viable