Proceedings of the 3rd Workshop on Domain-Specific Language Design and Implementation (DSLDI 2015)

The goal of the DSLDI workshop is to bring together researchers and practitioners interested in sharing ideas on how DSLs should be designed, implemented, supported by tools, and applied in realistic application contexts. We are both interested in discovering how already known domains such as graph processing or machine learning can be best supported by DSLs, but also in exploring new domains that could be targeted by DSLs. More generally, we are interested in building a community that can drive forward the development of modern DSLs. These informal post-proceedings contain the submitted talk abstracts to the 3rd DSLDI workshop (DSLDI'15), and a summary of the panel discussion on Language Composition

COST Action IC 1402 ArVI: Runtime Verification Beyond Monitoring -- Activity Report of Working Group 1

This report presents the activities of the first working group of the COST Action ArVI, Runtime Verification beyond Monitoring. The report aims to provide an overview of some of the major core aspects involved in Runtime Verification. Runtime Verification is the field of research dedicated to the analysis of system executions. It is often seen as a discipline that studies how a system run satisfies or violates correctness properties. The report exposes a taxonomy of Runtime Verification (RV) presenting the terminology involved with the main concepts of the field. The report also develops the concept of instrumentation, the various ways to instrument systems, and the fundamental role of instrumentation in designing an RV framework. We also discuss how RV interplays with other verification techniques such as model-checking, deductive verification, model learning, testing, and runtime assertion checking. Finally, we propose challenges in monitoring quantitative and statistical data beyond detecting property violation

An Algebra of Synchronous Scheduling Interfaces

In this paper we propose an algebra of synchronous scheduling interfaces which combines the expressiveness of Boolean algebra for logical and functional behaviour with the min-max-plus arithmetic for quantifying the non-functional aspects of synchronous interfaces. The interface theory arises from a realisability interpretation of intuitionistic modal logic (also known as Curry-Howard-Isomorphism or propositions-as-types principle). The resulting algebra of interface types aims to provide a general setting for specifying type-directed and compositional analyses of worst-case scheduling bounds. It covers synchronous control flow under concurrent, multi-processing or multi-threading execution and permits precise statements about exactness and coverage of the analyses supporting a variety of abstractions. The paper illustrates the expressiveness of the algebra by way of some examples taken from network flow problems, shortest-path, task scheduling and worst-case reaction times in synchronous programming.Comment: In Proceedings FIT 2010, arXiv:1101.426

Hailstorm : A Statically-Typed, Purely Functional Language for IoT Applications

With the growing ubiquity of Internet of Things (IoT), more complex logic is being programmed on resource-constrained IoT devices, almost exclusively using the C programming language. While C provides low-level control over memory, it lacks a number of high-level programming abstractions such as higher-order functions, polymorphism, strong static typing, memory safety, and automatic memory management.We present Hailstorm, a statically-typed, purely functional programming language that attempts to address the above problem. It is a high-level programming language with a strict typing discipline. It supports features like higher-order functions, tail-recursion and automatic memory management, to program IoT devices in a declarative manner. Applications running on these devices tend to be heavily dominated by I/O. Hailstorm tracks side effects like I/O in its type system using resource types. This choice allowed us to explore the design of a purely functional standalone language, in an area where it is more common to embed a functional core in an imperative shell. The language borrows the combinators of arrowized FRP, but has discrete-time semantics. The design of the full set of combinators is work in progress, driven by examples. So far, we have evaluated Hailstorm by writing standard examples from the literature (earthquake detection, a railway crossing system and various other clocked systems), and also running examples on the GRiSP embedded systems board, through generation of Erlang

High integrity hardware-software codesign

Programmable logic devices (PLDs) are increasing in complexity and speed, and are being used as important components in safety-critical systems. Methods for developing high-integrity software for these systems are well-known, but this is not true for programmable logic. We propose a process for developing a system incorporating software and PLDs, suitable for safety critical systems of the highest levels of integrity. This process incorporates the use of Synchronous Receptive Process Theory as a semantic basis for specifying and proving properties of programs executing on PLDs, and extends the use of SPARK Ada from a programming language for safety-critical systems software to cover the interface between software and programmable logic. We have validated this approach through the specification and development of a substantial safety-critical system incorporating both software and programmable logic components, and the development of tools to support this work. This enables us to claim that the methods demonstrated are not only feasible but also scale up to realistic system sizes, allowing development of such safety-critical software-hardware systems to the levels required by current system safety standards

Type Oriented Parallel Programming

Context: Parallel computing is an important field within the sciences. With the emergence of multi, and soon many, core CPUs this is moving more and more into the domain of general computing. HPC programmers want performance, but at the moment this comes at a cost; parallel languages are either efficient or conceptually simple, but not both. Aim: To develop and evaluate a novel programming paradigm which will address the problem of parallel programming and allow for languages which are both conceptually simple and efficient. Method: A type-based approach, which allows the programmer to control all aspects of parallelism by the use and combination of types has been developed. As a vehicle to present and analyze this new paradigm a parallel language, Mesham, and associated compilation tools have also been created. By using types to express parallelism the programmer can exercise efficient, flexible control in a high level abstract model yet with a sufficiently rich amount of information in the source code upon which the compiler can perform static analysis and optimization. Results: A number of case studies have been implemented in Mesham. Official benchmarks have been performed which demonstrate the paradigm allows one to write code which is comparable, in terms of performance, with existing high performance solutions. Sections of the parallel simulation package, Gadget-2, have been ported into Mesham, where substantial code simplifications have been made. Conclusions: The results obtained indicate that the type-based approach does satisfy the aim of the research described in this thesis. By using this new paradigm the programmer has been able to write parallel code which is both simple and efficient

Language Design for Reactive Systems: On Modal Models, Time, and Object Orientation in Lingua Franca and SCCharts

Reactive systems play a crucial role in the embedded domain. They continuously interact with their environment, handle concurrent operations, and are commonly expected to provide deterministic behavior to enable application in safety-critical systems. In this context, language design is a key aspect, since carefully tailored language constructs can aid in addressing the challenges faced in this domain, as illustrated by the various concurrency models that prevent the known pitfalls of regular threads. Today, many languages exist in this domain and often provide unique characteristics that make them specifically fit for certain use cases. This thesis evolves around two distinctive languages: the actor-oriented polyglot coordination language Lingua Franca and the synchronous statecharts dialect SCCharts. While they take different approaches in providing reactive modeling capabilities, they share clear similarities in their semantics and complement each other in design principles. This thesis analyzes and compares key design aspects in the context of these two languages. For three particularly relevant concepts, it provides and evaluates lean and seamless language extensions that are carefully aligned with the fundamental principles of the underlying language. Specifically, Lingua Franca is extended toward coordinating modal behavior, while SCCharts receives a timed automaton notation with an efficient execution model using dynamic ticks and an extension toward the object-oriented modeling paradigm

A seamless, client-centric programming model for type safe web applications

We propose a new programming model for web applications which is (1) seamless; one program and one language is used to produce code for both client and server, (2) client-centric; the programmer takes the viewpoint of the client that runs code on the server rather than the other way around, (3) functional and type-safe, and (4) portable; everything is implemented as a Haskell library that implicitly takes care of all networking code. Our aim is to improve the painful and error-prone experience of today's standard development methods, in which clients and servers are coded in different languages and communicate with each other using ad-hoc protocols. We present the design of our library called Haste.App, an example web application that uses it, and discuss the implementation and the compiler technology on which it depends

Correct synthesis and integration of compiler-generated function units

PhD ThesisComputer architectures can use custom logic in addition to general pur- pose processors to improve performance for a variety of applications. The use of custom logic allows greater parallelism for some algorithms. While conventional CPUs typically operate on words, ne-grained custom logic can improve e ciency for many bit level operations. The commodi ca- tion of eld programmable devices, particularly FPGAs, has improved the viability of using custom logic in an architecture. This thesis introduces an approach to reasoning about the correctness of compilers that generate custom logic that can be synthesized to provide hardware acceleration for a given application. Compiler intermediate representations (IRs) and transformations that are relevant to genera- tion of custom logic are presented. Architectures may vary in the way that custom logic is incorporated, and suitable abstractions are used in order that the results apply to compilation for a variety of the design parameters that are introduced by the use of custom logic