arXiv subjects

Philipp Haller

Publications and source records attributed to Philipp Haller.

21 records · Page 2Linked to original sources

arXiv2016

Distributed Programming via Safe Closure Passing

Programming systems incorporating aspects of functional programming, e.g., higher-order functions, are becoming increasingly popular for large-scale distributed programming. New frameworks such as Apache Spark leverage functional techniques to provide high-level, declarative APIs for in-memory data analytics, often outperforming traditional "big data" frameworks like Hadoop MapReduce. However, widely-used programming models remain rather ad-hoc; aspects such as implementation trade-offs, static typing, and semantics are not yet well-understood. We present a new asynchronous programming model that has at its core several principles facilitating functional processing of distributed data. The emphasis of our model is on simplicity, performance, and expressiveness. The primary means of communication is by passing functions (closures) to distributed, immutable data. To ensure safe and efficient distribution of closures, our model leverages both syntactic and type-based restrictions. We report on a prototype implementation in Scala. Finally, we present preliminary experimental results evaluating the performance impact of a static, type-based optimization of serialization.

cs.PL↗

arXiv2015

Modular Responsive Web Design using Element Queries

Responsive Web Design (RWD) enables web applications to adapt to the characteristics of different devices such as screen size which is important for mobile browsing. Today, the only W3C standard to support this adaptability is CSS media queries. However, using media queries it is impossible to create applications in a modular way, because responsive elements then always depend on the global context. Hence, responsive elements can only be reused if the global context is exactly the same, severely limiting their reusability. This makes it extremely challenging to develop large responsive applications, because the lack of true modularity makes certain requirement changes either impossible or expensive to realize. In this paper we extend RWD to also include responsive modules, i.e., modules that adapt their design based on their local context independently of the global context. We present the ELQ project which implements our approach. ELQ is a novel implementation of so-called element queries which generalize media queries. Importantly, our design conforms to existing web specifications, enabling adoption on a large scale. ELQ is designed to be heavily extensible using plugins. Experimental results show speed-ups of the core algorithms of up to 37x compared to previous approaches.

cs.SE↗

arXiv2015

A Formal Model for Direct-style Asynchronous Observables

Languages like F#, C#, and recently also Scala, provide "Async" programming models which aim to make asynchronous programming easier by avoiding an inversion of control that is inherent in callback-based programming models. This paper presents a novel approach to integrate the Async model with observable streams of the Reactive Extensions model. Reactive Extensions are best-known from the .NET platform, and widely-used implementations of its programming model exist also for Java, Ruby, and other languages. This paper contributes a formalization of the unified "Reactive Async" model in the context of an object-based core calculus. Our formal model captures the essence of the protocol of asynchronous observables using a heap evolution property. We prove a subject reduction theorem; the theorem implies that reduction preserves the heap evolution property. Thus, for well-typed programs our calculus ensures the protocol of asynchronous observables.

cs.PL↗