REBLS 2019- Proceedings of the 6th ACM SIGPLAN International Workshop on Reactive and Event-Based Languages and Systems

Concurrency control is difficult in JavaScript programs, where event race due to asynchronous computation is a major source of errors. While methods such as promises, cancellation tokens, and reactive programming offer their own advantages in addressing this problem, none offer a complete solution.

In this work, we present an integrated solution for concurrency control of JavaScript using a library, arrowjs, which is based on the abstraction of arrows. Arrowjs uses continuation passing style to chain callbacks and it implicitly generates progress objects to manage concurrency. Arrowjs can implement a form of push-based reactive programming, where event streams are arrow loops communicating through shared memory. Arrowjs thus provides interoperability between thread-like callback chains and event streams with a uniform concurrency control mechanism.

This paper presents an automatic parallelization method for a pure FRP language designed for embedded systems. Recent advances in microprocessor technology make it possible to use multicore processors even in resource-constrained embedded systems. To fully utilize such processors with a pure FRP language, we propose a method for parallelizing signal graph updates. The method is based on a static scheduling algorithm because it should run with a simple RTOS or without the help of operating systems. To evaluate the proposed method, we implemented a parallelizing compiler for XFRP, a pure FRP language for embedded systems. In this paper, we describe the parallelizing method and show some preliminary evaluation results using Linux-based systems that demonstrate the effectiveness of the method.

High resource utilization is important to operate compute infrastructures and data centers efficiently. High utilization is achieved by multiplexing several applications over the same physical infrastructure. Yet, with this approach, the different requirements of each application have to be taken into account when scheduling resources. We propose GRASS, a reactive domain-specific abstraction that allows specifying application-tailored resource scheduling policies. We demonstrate how the declarative approach of GRASS enables extension and composition of scheduling policies. Our evaluation shows the performance benefits of considering application-specific information in a composition of scheduling policies that adapt at run time.

Event-based parsing is a largely unexplored problem. Despite several hugely popular event-based parsers like SAX, there is very little research on the ways grammar engineers can be given explicit control over handling input tokens, and the consequences of exposing this control. Tool support is also underwhelming, with no language workbenches and very few libraries to help a parser developer to get started quickly and efficiently. To explore this paradigm, we have designed a language for event-based parsing and developed a prototype that translates specifications written in that language, to parsers in C#. We also report on the comparative performance of one of the parsers we generated, and a previously used PEG parser extracted from a real compiler.