Pure Object-oriented Languages Research Articles

Towards a taxonomy of Roxygen documentation in R packages

Software documentation is often neglected, impacting maintenance and reuse and leading to technical issues. In particular, when working with scientific software, such issues in the documentation pose a risk to producing reliable scientific results as they may cause improper or incorrect use of the software. R is a popular programming language for scientific software with a prolific package-based ecosystem, where users contribute packages (i.e., libraries). R packages are intended to be reused, and their users rely extensively on the available documentation. Thus, understanding what information developers provide in their packages’ documentation (generally, through a system known as Roxygen, based on Javadoc) is essential to contribute to it. This study mined 379 GitHub repositories of R packages and analysed a sample to develop a taxonomy of natural language descriptions used in Roxygen documentation. This was done through hybrid card sorting, which included two experienced R developers. The resulting taxonomy covers parameters, returns, and descriptions, providing a baseline for further studies. Our taxonomy is the first of its kind for R. Based on previous studies in pure object-oriented languages, our taxonomy could be extensible to other dynamically-typed languages used in scientific programming.

Memory Representations in Rewriting Logic Semantics Definitions

The executability of rewriting logic makes it a compelling environment for language design and experimentation; the ability to interpret programs directly in the language semantics develops assurance that definitions are correct and that language features work well together. However, this executability raises new questions about language semantics that don't necessarily make sense with non-executable definitions. For instance, suddenly the performance of the semantics, not just language interpreters or compilers based on the semantics, can be important, and representations must be chosen carefully to ensure that executing programs directly in language definitions is still feasible. Unfortunately, many obvious representations common in other semantic formalisms can lead to poor performance, including those used to represent program memory. This paper describes two different memory representations designed to improve performance: the first, which has been fully developed, is designed for use in imperative programs, while the second, still being developed, is intended for use in a variety of languages, with a special focus on pure object-oriented languages. Each representation is described and compared to the initial representation used in the language semantics, with thoughts on reuse also presented.

Uniform and safe metaclass composition

In pure object-oriented languages, classes are objects, instances of other classes called metaclasses. In the same way as classes define the properties of their instances, metaclasses define the properties of classes. It is therefore very natural to wish to reuse class properties, utilizing them amongst several classes. However this introduced metaclass composition problems, i.e., code fragments applied to one class may break when used on another class due to the inheritance relationship between their respective metaclasses. Numerous approaches have tried to solve metaclass composition problems, but they always resort to an ad-hoc manner of handling conflicting properties, alienating the meta-programmer. We propose a uniform approach that represents class properties as traits, groups of methods that act as a unit of reuse from which classes are composed. Like all the other classes in the system, metaclasses are composed out of traits. This solution supports the reuse of class properties, and their safe and automatic composition based on explicit conflict resolution. The paper discusses traits and our solution, shows concrete examples implemented in the Smalltalk environment Squeak, and compares our approach with existing models for composing class properties.

Efficient Execution of Pure Object-Oriented Programs by Follow-up Compilation

Dynamic type checking and method binding slows pure object-oriented programs such as those written in Smalltalk. Dynamic method lookup is needed to support method overriding and type-method conformance. We have developed a platform independent technique that implements method overriding efficiently for pure object-oriented languages. The technique involves binding non-overridden method calls at compile time. The overridden method calls are also resolved (and bound) statically using simple inferences. Overridden method bindings are corrected dynamically using an Overridden Method Dictionary. Using simulations, we demonstrate that this technique offers 35%-70% reduction in the average method lookup delay over the Berkeley Smalltalk implementation. This technique has very low compile time overhead, memory overhead, does not need specialized hardware and allows shared code pages in concurrent programs. For programs which may be re-used, it is proper to have a follow-up compilation to generate efficient code after the program development is complete.

Vortex

Previously, techniques such as class hierarchy analysis and profile-guided receiver class prediction have been demonstrated to greatly improve the performance of applications written in pure object-oriented languages, but the degree to which these results are transferable to applications written in hybrid languages has been unclear. In part to answer this question, we have developed the Vortex compiler infrastructure, a language-independent optimizing compiler for object-oriented languages, with front-ends for Cecil, C++, Java, and Modula-3. In this paper, we describe the Vortex compiler's intermediate language, internal structure, and optimization suite, and then we report the results of experiments assessing the effectiveness of different combinations of optimizations on sizable applications across these four languages. We characterize the benchmark programs in terms of a collection of static and dynamic metrics, intended to quantify aspects of the "object-orientedness" of a program.

Reconciling responsiveness with performance in pure object-oriented languages

Dynamically dispatched calls often limit the performance of object-oriented programs, since opject-oriented programming encourages factoring code into small, reusable units, thereby increasing the frequency of these expensive operations. Frequent calls not only slow down execution with the dispatch overhead per se, but more importantly they hinder optimization by limiting the range and effectiveness of standard global optimizations. In particular, dynamically dispatched calles prevent standard interprocedual optimizations that depend on the availability of a static call graph. The SELF implementation described here offers tow novel approaches to optimization. Type feedback speculatively inlines dynamically dispatched calls based on profile information that predicts likely receiver classes. Adaptive optimization reconciles optimizing compilation with interactive performance by incrementally optimizing only the frequently executed parts of a program. When combined, these two techniques result in a system that can execute programs significantly faster than previous systems while retaining much of the interactiveness of an interpreted system.

Profile-guided receiver class prediction

The use of dynamically-dispatched procedure calls is a key mechanism for writing extensible and flexible code in object-oriented languages. Unfortunately, dynamic dispatching imposes a runtime performance penalty. Some recent implementations of pure object-oriented languages have utilized profile-guided receiver class prediction to reduce this performance penalty, and some researchers have argued for applying receiver class prediction in hybrid languages like C++. We performed a detailed examination of the dynamic profiles of eight large object-oriented applications written in C++ and Cecil, determining that the receiver class distributions are strongly peaked and stable across both inputs and program versions through time. We describe techniques for gathering and manipulating profile information at varying degrees of precision, particularly in the presence of optimizations such as inlining. Our implementation of profile-guided receiver class prediction improves the performance of large Cecil applications by more than a factor of two over solely static optimizations.

Higher order objects in pure object-oriented languages

In this paper we present a method of directly translating higher order functions from functional programs into object-oriented programs. We show how to pass methods to generalized algorithms in pure object-oriented languages without extending the language. The translation allows partial parameterization, including currying, and conforms to strong typing. Finally we compare our method with conventional object-oriented approaches in terms of locality and reusability.

A third-generation SELF implementation

Programming systems should be both responsive (to support rapid development) and efficient (to complete computations quickly). Pure object-oriented languages are harder to implement efficiently since they need optimization to achieve good performance. Unfortunately, optimization conflicts with interactive responsiveness because it tends to produce long compilation pauses, leading to unresponsive programming environments. Therefore, to achieve good responsiveness, existing exploratory programming environments such as the Smalltalk-80 environment rely on interpretation or non-optimizing dynamic compilation. But such systems pay a price for their interactiveness, since they may execute programs several times slower than an optimizing system. SELF-93 reconciles high performance with responsiveness by combining a fast, non-optimizing compiler with a slower, optimizing compiler. The resulting system achieves both excellent performance (two or three times faster than existing Smalltalk systems) and good responsiveness. Except for situations requiring large applications to be (re)compiled from scratch, the system allows for pleasant interactive use with few perceptible compilation pauses. To our knowledge, SELF-93 is the first implementation of a pure object-oriented language achieving both good performance and good responsiveness. When measuring interactive pauses, it is imperative to treat multiple short pauses as one longer pause if the pauses occur in short succession, since they are perceived as one pause by the user. We propose a definition of pause clustering and show that clustering can make an order-of-magnitude difference in the pause time distribution.

Higher order objects in pure object-oriented languages

In this paper we present a method of directly translating higher order functions from functional programs into object-oriented programs. We show how to pass methods to generalized algorithms in pure object-oriented languages without extending the language. The translation allows partial parameterization, including currying, and conforms to strong typing. Finally we compare our method with conventional object-oriented approaches in terms of locality and reusability.

Making pure object-oriented languages practical

article Free Access Share on Making pure object-oriented languages practical Authors: Craig Chambers Department Computer Science and Engineering, Sieg Hall, FR-35, University of Washington, Seattle, WA and Stanford University Department Computer Science and Engineering, Sieg Hall, FR-35, University of Washington, Seattle, WA and Stanford UniversityView Profile , David Ungar Sun Laboratories, MS 29-116, 2550 Garcia Ave., Mountain View, CA and Stanford University Sun Laboratories, MS 29-116, 2550 Garcia Ave., Mountain View, CA and Stanford UniversityView Profile Authors Info & Claims ACM SIGPLAN NoticesVolume 26Issue 11Nov. 1991 pp 1–15https://doi.org/10.1145/118014.117955Online:01 November 1991Publication History 106citation527DownloadsMetricsTotal Citations106Total Downloads527Last 12 Months29Last 6 weeks7 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF