Querypoint Debugging

To fix a bug, software developers have to examine the bug-gy execution to locate defects. They employ different ap-proaches (e.g., setting breakpoints, inserting printing statements in the code) to navigate over buggy execution and inspect program state at suspicious points. In this pa-per we describe Querypoints, a new kind of compound conditional breakpoint relating two execution points. De-velopers specify Querypoints relative to a successfully paused conventional breakpoint or conventional watchpoint or to another Querypoint. The relative conditions contain runtime data values, like the last time a value was changed, or program statements, like the last conditional branch. The Querypoint combines the program state information from two execution points in the same execution; Querypoints can be chained to work backwards from effects to causes in a program. We present basic Querypoint concepts, two sample Que-rypoints, lastChange and lastCondition, and a description of our implementation of these Querypoints. To demon-strate that Querypoints are feasible we describe a prototype that implements an alternative approach to finding a bug in a graphical program analyzed previously with Whyline, one of the new logging-based debuggers

Revisiting Language Support for Generic Programming: When Genericity Is a Core Design Goal

Context Generic programming, as defined by Stepanov, is a methodology for writing efficient and reusable algorithms by considering only the required properties of their underlying data types and operations. Generic programming has proven to be an effective means of constructing libraries of reusable software components in languages that support it. Generics-related language design choices play a major role in how conducive generic programming is in practice. Inquiry Several mainstream programming languages (e.g. Java and C++) were first created without generics; features to support generic programming were added later, gradually. Much of the existing literature on supporting generic programming focuses thus on retrofitting generic programming into existing languages and identifying related implementation challenges. Is the programming experience significantly better, or different when programming with a language designed for generic programming without limitations from prior language design choices? Approach We examine Magnolia, a language designed to embody generic programming. Magnolia is representative of an approach to language design rooted in algebraic specifications. We repeat a well-known experiment, where we put Magnolia’s generic programming facilities under scrutiny by implementing a subset of the Boost Graph Library, and reflect on our development experience. Knowledge We discover that the idioms identified as key features for supporting Stepanov-style generic programming in the previous studies and work on the topic do not tell a full story. We clarify which of them are more of a means to an end, rather than fundamental features for supporting generic programming. Based on the development experience with Magnolia, we identify variadics as an additional key feature for generic programming and point out limitations and challenges of genericity by property. Grounding Our work uses a well-known framework for evaluating the generic programming facilities of a language from the literature to evaluate the algebraic approach through Magnolia, and we draw comparisons with well-known programming languages. Importance This work gives a fresh perspective on generic programming, and clarifies what are fundamental language properties and their trade-offs when considering supporting Stepanov-style generic programming. The understanding of how to set the ground for generic programming will inform future language design.publishedVersio

Revisiting Language Support for Generic Programming: When Genericity Is a Core Design Goal

ContextGeneric programming, as defined by Stepanov, is a methodology for writing efficient and reusable algorithms by considering only the required properties of their underlying data types and operations. Generic programming has proven to be an effective means of constructing libraries of reusable software components in languages that support it. Generics-related language design choices play a major role in how conducive generic programming is in practice.InquirySeveral mainstream programming languages (e.g. Java and C++) were first created without generics; features to support generic programming were added later, gradually. Much of the existing literature on supporting generic programming focuses thus on retrofitting generic programming into existing languages and identifying related implementation challenges. Is the programming experience significantly better, or different when programming with a language designed for generic programming without limitations from prior language design choices?ApproachWe examine Magnolia, a language designed to embody generic programming. Magnolia is representative of an approach to language design rooted in algebraic specifications. We repeat a well-known experiment, where we put Magnolia’s generic programming facilities under scrutiny by implementing a subset of the Boost Graph Library, and reflect on our development experience.KnowledgeWe discover that the idioms identified as key features for supporting Stepanov-style generic programming in the previous studies and work on the topic do not tell a full story. We clarify which of them are more of a means to an end, rather than fundamental features for supporting generic programming. Based on the development experience with Magnolia, we identify variadics as an additional key feature for generic programming and point out limitations and challenges of genericity by property.GroundingOur work uses a well-known framework for evaluating the generic programming facilities of a language from the literature to evaluate the algebraic approach through Magnolia, and we draw comparisons with well-known programming languages.ImportanceThis work gives a fresh perspective on generic programming, and clarifies what are fundamental language properties and their trade-offs when considering supporting Stepanov-style generic programming. The understanding of how to set the ground for generic programming will inform future language design.</p

Enhancement of natural language processing approach for automated generation of object constraint language

Object Constraint Language (OCL) is the most prevalent modeling language to document requirement constraints that are annotated in the Unified Modeling Language. Various researchers have proved that OCL syntax is complex and difficult for some reasons such as its declarative nature. As the measure of ease-of-use factor of a language has a direct relationship with the language’s usability, the difficulties in the use of OCL result in the low usability of OCL. There are few research works for OCL generation using some different techniques such as pattern-based and Model-Driven Architecture (MDA)-based. The accuracy of the existing patternbased work generating OCL specification is low. MDA focuses on software development based on generating models and transforming these models between each other. There are some researches based on MDA to increase the usability of modeling languages. However, only one of the existing works supports OCL. The existing MDA-based work generating OCL specification does not support some OCL elements, such as collect and reject, and some UML elements such as enumeration. Therefore, this research proposes an MDA-based approach to transform requirement constraints formed in English sentences into OCL specifications using transformation rules. A software tool is developed to validate the proposed approach and compare with the existing works. The comparison shows that the proposed approach solves some limitations of the existing works such as support of some OCL and UML elements, which are not supported by the existing works. The comparison also shows that some accuracy improvement is achieved by the proposed approach in comparison with the existing works

Fuel: A Fast General Purpose Object Graph Serializer

International audienceSince objects need to be stored and reloaded on different environments, serializing object graphs is a very important activity. There is a plethora of serialization frameworks with different requirements and design trade-offs. Most of them are based on recursive parsing of the object graphs, an approach which often is too slow. In addition, most of them prioritize a language-agnostic format instead of speed and language-specific object serialization. For the same reason, such serializers usually do not support features like class-shape changes, global references or executing pre and post load actions. Looking for speed, some frameworks are partially implemented at Virtual Machine (VM) level, hampering code portability and making them difficult to understand, maintain and extend. In this paper we present Fuel, a general-purpose object serializer based on these principles: (1) speed, through a compact binary format and a pickling algorithm which invests time in serialization for obtaining the best performance on materialization; (2) good object-oriented design, without special help at VM; (3) serialize any object, thus have a full-featured language-specific format. We implement and validate this approach in Pharo, where we demonstrate that Fuel is faster than other serializers, even those with special VM support. The extensibility of Fuel made possible to successfully serialize various objects: classes in Newspeak, debugger stacks, and full CMS object graphs

Languages of games and play: A systematic mapping study

Digital games are a powerful means for creating enticing, beautiful, educational, and often highly addictive interactive experiences that impact the lives of billions of players worldwide. We explore what informs the design and construction of good games to learn how to speed-up game development. In particular, we study to what extent languages, notations, patterns, and tools, can offer experts theoretical foundations, systematic techniques, and practical solutions they need to raise their productivity and improve the quality of games and play. Despite the growing number of publications on this topic there is currently no overview describing the state-of-the-art that relates research areas, goals, and applications. As a result, efforts and successes are often one-off, lessons learned go overlooked, language reuse remains minimal, and opportunities for collaboration and synergy are lost. We present a systematic map that identifies relevant publications and gives an overview of research areas and publication venues. In addition, we categorize research perspectives along common objectives, techniques, and approaches, illustrated by summaries of selected languages. Finally, we distill challenges and opportunities for future research and development

First-class features

Magdeburg, Univ., Fak. für Informatik, Diss., 2011von Sagar Sunkl