Choosing the right tools for teaching programming, which is a difficult task by itself, is not easy. Which language can be effectively used depends on the language itself, the chosen approach at which paradigm to teac...
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We present an abstract, set-theoretic denotational semantics for a significant subset of OCaml and its module system, allowing to reason about the correctness of renaming value bindings. Our semantics captures informa...
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ISBN:
(纸本)9781450367127
We present an abstract, set-theoretic denotational semantics for a significant subset of OCaml and its module system, allowing to reason about the correctness of renaming value bindings. Our semantics captures information about the binding structure of programs, as well as about which declarations are related by the use of different language constructs (e.g. functors, module types and module constraints). Correct renamings are precisely those that preserve this structure. We show that our abstract semantics is sound with respect to a (domain-theoretic) denotational model of the operational behaviour of programs, and that it allows us to prove various high-level, intuitive properties of renamings. This formal framework has been implemented in a prototype refactoring tool for OCaml that performs renaming.
作者：
Mosses, Peter D.Swansea Univ
Dept Comp Sci Computat Foundry Bay Campus Swansea SA1 8EN W Glam Wales Delft Univ Technol
Programming Languages EEMCS POB 5031 NL-2600 GA Delft Netherlands
The SLE conference series is devoted to the engineering principles of software languages: their design, their implementation, and their evolution. This paper is about the role of language specification in SLE. A preci...
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The SLE conference series is devoted to the engineering principles of software languages: their design, their implementation, and their evolution. This paper is about the role of language specification in SLE. A precise specification of a software language needs to be written in a formal meta-language, and it needs to co-evolve with the specified language. Moreover, different software languages often have features in common, which should provide opportunities for reuse of parts of language specifications. Support for co-evolution and reuse in a meta-language requires careful engineering of its design. The author has been involved in the development of several meta-languages for semantic specification, including action semantics and modular variants of structural operational semantics (MSOS, I-MSOS). This led to the PLanCompS project, and to the design of its meta-language, CBS, for component-based semantics. CBS comes together with an extensible library of reusable components called 'funcons', corresponding to fundamental programming constructs. The main aim of CBS is to optimise co-evolution and reuse of specifications during language development, and to make specification of language semantics almost as straightforward as context-free syntax specification. The paper discusses the engineering of a selection of previous meta-languages, assessing how well they support co-evolution and reuse. It then gives an introduction to CBS, and illustrates significant features. It also considers whether other current meta-languages might also be used to define an extensible library of funcons for use in component-based semantics.
This poster presents an Interactive Tutoring System (ITS) that allows teachers to tutor and evaluate interactively the learning process that the students of a Compiler design course must experience from each theoretic...
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ISBN:
(纸本)9781450368742
This poster presents an Interactive Tutoring System (ITS) that allows teachers to tutor and evaluate interactively the learning process that the students of a Compiler design course must experience from each theoretical concept to obtain the code of its corresponding implementation (scanners, parsers, translators, interpreters, compilers), regardless of the specific tools chosen for the automatic code generation and the programminglanguage. Through the use of the ITS, each teacher will be able to select those tools that he/she considers more adequate for the development of the course, and integrate them modularly into a common educational environment, so that if later on she/he decides to change these tools or the programminglanguage, the ITS will continue to be valid, and the tutoring and evaluation process carried out by the ITS will remain the same to guide the students from theory to implementation.
Polyglot programming provides software developers with a broader choice in terms of software libraries and frameworks available for building applications. Previous research and engineering activities have focused on l...
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ISBN:
(纸本)9781450369770
Polyglot programming provides software developers with a broader choice in terms of software libraries and frameworks available for building applications. Previous research and engineering activities have focused on language interoperability and the design and implementation of fast polyglot runtimes. To make polyglot programming more approachable for developers, novel software development tools are needed that help them build polyglot applications. We believe a suitable prototyping platform helps to more quickly evaluate new ideas for such tools. In this paper we present GraalSqueak, a Squeak/Smalltalk virtual machine implementation for the GraalVM. We report our experience implementing GraalSqueak, evaluate the performance of the language and the programming environment, and discuss how the system can be used as a tooling platform for polyglot programming.
Although probabilistic programming is widely used for some restricted classes of statistical models, existing systems lack the flexibility and efficiency needed for practical use with more challenging models arising i...
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ISBN:
(纸本)9781450367127
Although probabilistic programming is widely used for some restricted classes of statistical models, existing systems lack the flexibility and efficiency needed for practical use with more challenging models arising in fields like computer vision and robotics. This paper introduces Gen, a generalpurpose probabilistic programming system that achieves modeling flexibility and inference efficiency via several novel language constructs: (i) the generative function interface for encapsulating probabilistic models;(ii) interoperable modeling languages that strike different flexibility/efficiency tradeoffs;(iii) combinators that exploit common patterns of conditional independence;and (iv) an inference library that empowers users to implement efficient inference algorithms at a high level of abstraction. We show that Gen outperforms state-of-the-art probabilistic programming systems, sometimes by multiple orders of magnitude, on diverse problems including object tracking, estimating 3D body pose from a depth image, and inferring the structure of a time series.
We propose a new probabilistic programminglanguage for the design and analysis of perception systems, especially those based on machine learning. Specifically, we consider the problems of training a perception system...
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ISBN:
(纸本)9781450367127
We propose a new probabilistic programminglanguage for the design and analysis of perception systems, especially those based on machine learning. Specifically, we consider the problems of training a perception system to handle rare events, testing its performance under different conditions, and debugging failures. We show how a probabilistic programminglanguage can help address these problems by specifying distributions encoding interesting types of inputs and sampling these to generate specialized training and test sets. More generally, such languages can be used for cyber-physical systems and robotics to write environment models, an essential prerequisite to any formal analysis. In this paper, we focus on systems like autonomous cars and robots, whose environment is a scene, a configuration of physical objects and agents. We design a domain-specific language, Scenic, for describing scenarios that are distributions over scenes. As a probabilistic programminglanguage, Scenic allows assigning distributions to features of the scene, as well as declaratively imposing hard and soft constraints over the scene. We develop specialized techniques for sampling from the resulting distribution, taking advantage of the structure provided by Scenic's domain-specific syntax. Finally, we apply Scenic in a case study on a convolutional neural network designed to detect cars in road images, improving its performance beyond that achieved by state-of-the-art synthetic data generation methods.
This paper presents McNetKAT, a scalable tool for verifying probabilistic network programs. McNetKAT is based on a new semantics for the guarded and history-free fragment of Probabilistic NetKAT in terms of finite-sta...
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ISBN:
(纸本)9781450367127
This paper presents McNetKAT, a scalable tool for verifying probabilistic network programs. McNetKAT is based on a new semantics for the guarded and history-free fragment of Probabilistic NetKAT in terms of finite-state, absorbing Markov chains. This view allows the semantics of all programs to be computed exactly, enabling construction of an automatic verification tool. Domain-specific optimizations and a parallelizing backend enable McNetKAT to analyze networks with thousands of nodes, automatically reasoning about general properties such as probabilistic program equivalence and refinement, as well as networking properties such as resilience to failures. We evaluate McNetKAT's scalability using real-world topologies, compare its performance against state-of-the-art tools, and develop an extended case study on a recently proposed data center network design.
JavaScript performance is paramount to a user's browsing experience. Browser vendors have gone to great lengths to improve JavaScript's steady-state performance. This has led to sophisticated web applications....
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ISBN:
(纸本)9781450367127
JavaScript performance is paramount to a user's browsing experience. Browser vendors have gone to great lengths to improve JavaScript's steady-state performance. This has led to sophisticated web applications. However, as users increasingly expect instantaneous page load times, another important goal for JavaScript engines is to attain minimal startup times. In this paper, we reduce the startup time of JavaScript programs by enhancing the reuse of compilation and optimization information across different executions. Specifically, we propose a new scheme to increase the startup performance of Inline Caching (IC), a key optimization for dynamic type systems. The idea is to represent a substantial portion of the IC information in an execution in a context-independent way, and reuse it in subsequent executions. We call our enhanced IC design Reusable Inline Caching (RIC). We integrate RIC into the state-of-the-art Google V8 JavaScript engine and measure its impact on the initialization time of popular JavaScript libraries. By recycling IC information collected from a previous execution, RIC reduces the average initialization time per library by 17%.
We derive a variant of quantum Hoare logic (QHL), called applied quantum Hoare logic (aQHL for short), by: (1) restricting QHL to a special class of preconditions and postconditions, namely projections, which can sign...
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ISBN:
(纸本)9781450367127
We derive a variant of quantum Hoare logic (QHL), called applied quantum Hoare logic (aQHL for short), by: (1) restricting QHL to a special class of preconditions and postconditions, namely projections, which can significantly simplify verification of quantum programs and are much more convenient when used in debugging and testing;and (2) adding several rules for reasoning about robustness of quantum programs, i.e. error bounds of outputs. The effectiveness of aQHL is shown by its applications to verify two sophisticated quantum algorithms: HHL (Harrow-Hassidim-Lloyd) for solving systems of linear equations and qPCA (quantum Principal Component Analysis).
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