Journal of Computer Languages最新文献

{"title":"A new architecture reconciling refactorings and transformations","authors":"Balša Šarenac ,&nbsp;Nicolas Anquetil ,&nbsp;Stéphane Ducasse ,&nbsp;Pablo Tesone","doi":"10.1016/j.cola.2024.101273","DOIUrl":"https://doi.org/10.1016/j.cola.2024.101273","url":null,"abstract":"<div><p><em>Refactorings</em> are behavior-preserving code transformations. They are a recommended software development practice and are now a standard feature in modern IDEs. There are however many situations where developers need to perform mere <em>transformations</em> (non-behavior-preserving) or to mix refactorings and transformations. Little work exists on the analysis of transformations <em>implementation</em>, how refactorings could be composed of smaller, reusable, parts (simple transformations or other refactorings), and, conversely, how transformations could be <em>reused</em> in isolation or to compose new refactorings. In a previous article, we started to analyze the seminal implementation of refactorings as proposed in the Ph.D. of D. Roberts, and whose evolution is available in the Pharo IDE. We identified a dichotomy between the class hierarchy of <em>refactorings</em> (56 classes) and that of <em>transformations</em> (70 classes). We also noted that there are different kinds of preconditions for different purposes (applicability preconditions or behavior-preserving preconditions). In this article, we go further by proposing a new architecture that: (i) supports two important scenarios (interactive use or scripting, <em><em>i.e.,</em></em> batch use); (ii) defines a clear API unifying refactorings and transformations; (iii) expresses refactorings as decorators over transformations, and; (iv) formalizes the uses of the different kinds of preconditions, thus supporting better user feedback. We are in the process of migrating the existing Pharo refactorings to this new architecture. Current results show that elementary transformations such as the <span>Add Method</span> transformation is reused in 24 refactorings and 11 other transformations; and the <span>Remove Method</span> transformation is reused in 11 refactorings and 7 other transformations.</p></div>","PeriodicalId":48552,"journal":{"name":"Journal of Computer Languages","volume":"80 ","pages":"Article 101273"},"PeriodicalIF":2.2,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141312955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Towards a Dynabook for verified VM construction","authors":"Boris Shingarov ,&nbsp;Jan Vraný","doi":"10.1016/j.cola.2024.101275","DOIUrl":"10.1016/j.cola.2024.101275","url":null,"abstract":"<div><p>We present <em>Smalltalk-25</em>, a scientific <em>Programm</em> of research towards the synthesis of Smalltalk VMs by formal methods. We approach this through a Dynabook-style implementation of Hilbert’s “manipulating proofs as mathematical objects”. We begin by implementing an automated-reasoning engine based on refinement types. Having that foundation laid, we build a program logics for a simple “model” language; a framework for reasoning about a real intermediate language by translating into the model language; an ahead-of-time bootstrapper; and a framework for debugging thus-constructed VMs.</p><p>Our <em>Programm</em> is an ongoing research effort; this paper provides a report of its current status. Every part of our system is implemented in Smalltalk and available from GitHub under the MIT license.</p></div>","PeriodicalId":48552,"journal":{"name":"Journal of Computer Languages","volume":"80 ","pages":"Article 101275"},"PeriodicalIF":2.2,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141140750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pharo: A reflective language—Analyzing the reflective API and its internal dependencies","authors":"Iona Thomas,&nbsp;Stéphane Ducasse,&nbsp;Pablo Tesone,&nbsp;Guillermo Polito","doi":"10.1016/j.cola.2024.101274","DOIUrl":"10.1016/j.cola.2024.101274","url":null,"abstract":"<div><p>Reflective operations are powerful APIs (Application Programming Interface) that let developers build advanced tools and architectures. Reflective operations are used for implementing tools and development environments (<em>e.g.,</em> compilers, debuggers, inspectors) or language features (<em>e.g.,</em> distributed systems, exceptions, proxies, aspect-oriented programming). In addition, languages are evolving, introducing better concepts, and revising practices and APIs. Since 2008 Pharo has evolved from Squeak and its reflective API has evolved accordingly, diverging consequently from the original Smalltalk reflective API. With more than 500 reflective methods identified, Pharo has one of the largest reflective feature sets ranging from structural reflection to on-demand stack reification. Those operations are often built on top of the other, creating different layers of reflective operations, from low-level to high-level ones.</p><p>There is a need to understand the current reflective APIs to understand their underlying use, potential dependencies, and whether some reflective features can be scoped and optional. Such an analysis is challenged by new metaobjects organically introduced in the system, such as first-class instance variables, and their mixture with the base-level API of objects and classes.</p><p>In this article, we analyze the reflective operations used in Pharo 12 and their interdependencies. We propose a classification based on their semantics and we identify a set of issues of the current implementation. Such an analysis of reflective operations in Pharo is important to support the revision of the reflective layer and its potential redesign.</p></div>","PeriodicalId":48552,"journal":{"name":"Journal of Computer Languages","volume":"80 ","pages":"Article 101274"},"PeriodicalIF":2.2,"publicationDate":"2024-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141130163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Explanations for combinatorial optimization problems","authors":"Martin Erwig,&nbsp;Prashant Kumar","doi":"10.1016/j.cola.2024.101272","DOIUrl":"https://doi.org/10.1016/j.cola.2024.101272","url":null,"abstract":"<div><p>We introduce a representation for generating explanations for the outcomes of combinatorial optimization algorithms. The two key ideas are (A) to maintain fine-grained representations of the values manipulated by these algorithms and (B) to derive explanations from these representations through merge, filter, and aggregation operations. An explanation in our model presents essentially a high-level comparison of the solution to a problem with a hypothesized alternative, illuminating why the solution is better than the alternative. Our value representation results in explanations smaller than other dynamic program representations, such as traces. Based on a measure for the conciseness of explanations we demonstrate through a number of experiments that the explanations produced by our approach are small and scale well with problem size across a number of different applications.</p></div>","PeriodicalId":48552,"journal":{"name":"Journal of Computer Languages","volume":"79 ","pages":"Article 101272"},"PeriodicalIF":2.2,"publicationDate":"2024-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140880436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A fresh look on semantics of Concurrent State Based Language (ConStaBL)","authors":"Karthika Venkatesan ,&nbsp;Sujit Kumar Chakrabarti","doi":"10.1016/j.cola.2024.101270","DOIUrl":"https://doi.org/10.1016/j.cola.2024.101270","url":null,"abstract":"<div><p>Statechart is a visual modelling language for systems. Our variant of the statechart has local variables, which interact significantly with the remainder of the language semantics. It allows arbitrary interleaving of concurrently executing action code, which allows more precise modelling of systems and upstream analysis of the same. We also establish the criteria based on our semantics for defining conflicting transitions and valid simulations. Our semantics do not allow transition conflicts in simulations and are stricter than most other available semantics of statecharts in that sense. In this paper, we extend the work on modular statecharts and present updated operational semantics with concurrency. We present the operational semantics in the form of the simulation algorithm. Our executable semantics can be used to simulate statechart models and verify their correctness. We present a preliminary setup to carry out fuzz testing of statechart models, an idea that does not have precedent in the literature to the best of our knowledge. We have used our simulator in conjunction with a well-known fuzzer to do fuzz testing of statechart models of non-trivial sizes and have found issues in them that would have been hard to find through inspection.</p></div>","PeriodicalId":48552,"journal":{"name":"Journal of Computer Languages","volume":"79 ","pages":"Article 101270"},"PeriodicalIF":2.2,"publicationDate":"2024-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140880437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the use of statistical machine translation for suggesting variable names for decompiled code: The Pharo case","authors":"Juan Pablo Sandoval Alcocer ,&nbsp;Harold Camacho-Jaimes ,&nbsp;Geraldine Galindo-Gutierrez ,&nbsp;Andrés Neyem ,&nbsp;Alexandre Bergel ,&nbsp;Stéphane Ducasse","doi":"10.1016/j.cola.2024.101271","DOIUrl":"https://doi.org/10.1016/j.cola.2024.101271","url":null,"abstract":"<div><p>Adequately selecting variable names is a difficult activity for practitioners. In 2018, Jaffe et al. proposed the use of statistical machine translation (SMT) to suggest descriptive variable names for decompiled code. A large corpus of decompiled C code was used to train the SMT model. Our paper presents the results of a partial replication of Jaffe’s experiment. We apply the same technique and methodology to a dataset made of code written in the Pharo programming language. We selected Pharo since its syntax is simple – it fits on half of a postcard – and because the optimizations performed by the compiler are limited to method scope. Our results indicate that SMT may recover between 8.9% and 69.88% of the variable names depending on the training set. Our replication concludes that: (i) the accuracy depends on the code similarity between the training and testing sets; (ii) the simplicity of the Pharo syntax and the satisfactory decompiled code alignment have a positive impact on predicting variable names; and (iii) a relatively small code corpus is sufficient to train the SMT model, which shows the applicability of the approach to less popular programming languages. Additionally, to assess SMT’s potential in improving original variable names, ten Pharo developers reviewed 400 SMT name suggestions, with four reviews per variable. Only 15 suggestions (3.75%) were unanimously viewed as improvements, while 45 (11.25%) were perceived as improvements by at least two reviewers, highlighting SMT’s limitations in providing suitable alternatives.</p></div>","PeriodicalId":48552,"journal":{"name":"Journal of Computer Languages","volume":"79 ","pages":"Article 101271"},"PeriodicalIF":2.2,"publicationDate":"2024-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140643845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An empirical approach to understand the role of emotions in code comprehension","authors":"Divjot Singh,&nbsp;Ashutosh Mishra,&nbsp;Ashutosh Aggarwal","doi":"10.1016/j.cola.2024.101269","DOIUrl":"https://doi.org/10.1016/j.cola.2024.101269","url":null,"abstract":"<div><p>Programming and cognitive skills are two pivotal abilities of programmers to maintain software products. First, this study included a systematic literature review on code comprehension, emotions, cognitive psychology, and belief-desire-intention domains to analyse various code comprehension monitoring techniques, performance metrics, and computational methodologies. Second, a case study is conducted to examine the influence of various emotional stages on programmers’ programming and cognitive skills while comprehending the software code. The categorization of the participants is done empirically based on their expertism level, and the same results are verified using various machine learning models and performance metrics.</p></div>","PeriodicalId":48552,"journal":{"name":"Journal of Computer Languages","volume":"79 ","pages":"Article 101269"},"PeriodicalIF":2.2,"publicationDate":"2024-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140052825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"WARDuino: An embedded WebAssembly virtual machine","authors":"Tom Lauwaerts,&nbsp;Robbert Gurdeep Singh ,&nbsp;Christophe Scholliers","doi":"10.1016/j.cola.2024.101268","DOIUrl":"10.1016/j.cola.2024.101268","url":null,"abstract":"<div><p>Creating IoT programs for resource-constrained microcontrollers differs significantly from conventional computer programming. Microcontrollers are traditionally programmed using low-level programming languages with poor debugging facilities. By contrast, general-purpose systems can be programmed with high-level languages, which make programming easier by providing many useful tools such as advanced debuggers, strong type systems, and/or automatic memory management. Most existing solutions for programming microcontrollers with high-level languages are strongly tied to a specific microcontroller architecture, which makes porting code difficult or impossible. In addition, compiling and flashing software onto a microcontroller is time-consuming, slowing down development.</p><p>To solve these problems we present WARDuino, a WebAssembly virtual machine that runs on microcontrollers and provides WebAssembly primitives to control embedded hardware and IoT functionality. WARDuino runs programs written in a plethora of high-level languages that compile to WebAssembly. We give a general approach for language integration libraries to expose the peripherals and networking capabilities of the device following the idioms of the host language.</p><p>To ease development, we extend WebAssembly with support for remote debugging and over-the-air reprogramming. WARDuino can remotely instruct a microcontroller to pause, to step, or to dump its state, and to replace local variables, functions or even the entire running program. We use the remote debugger of the virtual machine to create a visual debugging environment in VS Code for WARDuino, that can debug WebAssembly and AssemblyScript. Aside from these important tools, we provide a novel mechanism to handle asynchronous interrupts in WebAssembly, a fundamental building block for responsive embedded applications. Our extensions are implemented in the WARDuino virtual machine and presented as formal extensions to the WebAssembly operational semantics. We use the formalization to proof observational equivalence for the core debugger semantics.</p><p>We compared the computational performance and memory size with native C code, Espruino, and WASM3 which compiles WebAssembly ahead-of-time. The comparison shows that WARDuino’s performance is acceptable. Although WARDuino is on average 425.93 times slower than native code and 37.96 times slower than WASM3, it outperforms the popular Espruino runtime by a factor of 11.66. Additionally, we show that WARDuino is fast enough to program traditional IoT applications that handle network and device interrupts with a classic smart lamp application written in AssemblyScript.</p></div>","PeriodicalId":48552,"journal":{"name":"Journal of Computer Languages","volume":"79 ","pages":"Article 101268"},"PeriodicalIF":2.2,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139891428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Developers’ information seeking in Question & Answer websites through a gender lens","authors":"Abim Sedhain ,&nbsp;Vaishvi Diwanji ,&nbsp;Helen Solomon ,&nbsp;Shahnewaz Leon ,&nbsp;Sandeep Kaur Kuttal","doi":"10.1016/j.cola.2024.101267","DOIUrl":"10.1016/j.cola.2024.101267","url":null,"abstract":"<div><p>Question &amp; Answer websites for developers, such as Stack Overflow, contain enormous programming knowledge which can be redundant and cost substantial time and cognitive effort. We investigated the information seeking behavior of developers on Stack Overflow using Information Foraging Theory. To understand the influence of gender on foraging patterns, we conducted a gender-balanced think-aloud lab study with 12 participants, followed by retrospective interviews. The participants performed two debugging tasks: (1) understand foraging between question variants and (2) understand foraging between answer variants, on Stack Overflow. Various cues and strategies were utilized by the participants to find relevant question and optimal answer on Stack Overflow. The effect of gender on their foraging pattern was observed as male participants used 19.7% more cues and spent 55% more time than female participants. We also categorized various cues in terms of cost-value proposition and reported a debugging foraging model for Stack Overflow. Our study has implications for Question and Answer websites as well as Information Foraging Theory.</p></div>","PeriodicalId":48552,"journal":{"name":"Journal of Computer Languages","volume":"79 ","pages":"Article 101267"},"PeriodicalIF":2.2,"publicationDate":"2024-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139688544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"τJUpdate: An update language for time-varying JSON data","authors":"Zouhaier Brahmia ,&nbsp;Fabio Grandi ,&nbsp;Safa Brahmia ,&nbsp;Rafik Bouaziz","doi":"10.1016/j.cola.2024.101258","DOIUrl":"10.1016/j.cola.2024.101258","url":null,"abstract":"<div><p><span>Time-varying JSON data are being used and exchanged in various today’s application frameworks like IoT<span><span> platforms, Web services, cloud computing, </span>online social networks<span><span><span>, and mobile systems. However, in the state-of-the-art of JSON data management, there is neither a consensual nor a standard language for updating (i.e., inserting, modifying, and deleting) temporal JSON data, like the TSQL2 or SQL:2016 languages for temporal </span>relational data. Moreover, existing JSON-based NoSQL </span>DBMSs<span><span> (e.g., MongoDB, Couchbase, CouchDB, OrientDB, and Riak) and both commercial relational DBMSs (e.g., IBM DB2 12, Oracle 19c, and MS SQL Server 2019) and open-source ones (e.g., </span>PostgreSQL 15, and MySQL 8.0) supporting JSON documents do not provide any facility for maintaining temporal JSON data. Also in our previously proposed temporal JSON framework, called </span></span></span></span><span><math><mi>τ</mi></math></span>JSchema, there was no feature for temporal JSON instance updates. For these reasons, we propose in this article a temporal update language, named <span><math><mi>τ</mi></math></span>JUpdate (Temporal JUpdate), for JSON data in the <span><math><mi>τ</mi></math></span><span>JSchema environment. We define it as a temporal extension<span> of our previously introduced non-temporal JSON update language, named JUpdate (JSON Update). Both the syntax and the operational semantics of the data modification operations of JUpdate have been extended to support temporal aspects. </span></span><span><math><mi>τ</mi></math></span>JUpdate allows to specify temporal JSON updates in an expressive and user-friendly manner, and to efficiently execute them in the <span><math><mi>τ</mi></math></span>JSchema environment.</p></div>","PeriodicalId":48552,"journal":{"name":"Journal of Computer Languages","volume":"79 ","pages":"Article 101258"},"PeriodicalIF":2.2,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139460031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}