Indexed languages are a classical notion in formal language theory, which has attracted attention in recent decades due to its role in higher-order model checking: They are precisely the languages accepted by order-2 pushdown automata. The downward closure of an indexed language -- the set of all (scattered) subwords of its members -- is well-known to be a regular over-approximation. It was shown by Zetzsche (ICALP 2015) that the downward closure of a given indexed language is effectively computable. However, the algorithm comes with no complexity bounds, and it has remained open whether a primitive-recursive construction exists. We settle this question and provide a triply (resp.\ quadruply) exponential construction of a non-deterministic (resp.\ deterministic) automaton. We also prove (asymptotically) matching lower bounds. For the upper bounds, we rely on recent advances in semigroup theory, which let us compute bounded-size summaries of words with respect to a finite semigroup. By replacing stacks with their summaries, we are able to transform an indexed grammar into a context-free one with the same downward closure, and then apply existing bounds for context-free grammars.
Grammar inference for complex programming languages remains a significant challenge, as existing approaches fail to scale to real world datasets within practical time constraints. In our experiments, none of the state-of-the-art tools, including Arvada, Treevada and Kedavra were able to infer grammars for complex languages such as C, C++, and Java within 48 hours. Arvada and Treevada perform grammar inference directly on full-length input examples, which proves inefficient for large files commonly found in such languages. While Kedavra introduces data decomposition to create shorter examples for grammar inference, its lexical analysis still relies on the original inputs. Additionally, its strict no-overgeneralization constraint limits the construction of complex grammars. To overcome these limitations, we propose Crucio, which builds a decomposition forest to extract short examples for lexical and grammar inference via a distributional matrix. Experimental results show that Crucio is the only method capable of successfully inferring grammars for complex programming languages (where the number of nonterminals is up to 23x greater than in prior benchmarks) within reasonable time limits. On the prior simple benchmark, Crucio achieves an average recall improvement of 1.37x and 1.19x over Treevada and Kedavra, respectively, and improves F1 scores by 1.21x and 1.13x.
Anja Ballis, Lisa Schwendemann, Svenja Hahn
et al.
Virtual Reality (VR) eröffnet im Deutschunterricht neue Perspektiven literarisch-medialer Bildung – als ästhetisch-situativer Erfahrungsraum, Medium narrativer Teilhabe und didaktische Herausforderung. Der Beitrag stellt zwei explorative Studien vor: eine qualitative Untersuchung zur Goethe VR, in der Schüler:innen Goethes Faust immersiv aus der Perspektive der Hauptfigur des Faust erleben, sowie eine Fragebogenerhebung der dokumentarisch inszenierten Anne Frank House VR, die das subjektive Präsenzerleben in einem historischen Erinnerungsraum fokussiert und mit Zitaten aus Anne Franks Tagebuch anreichert.
Im Zentrum steht die Frage, wie kanonische Texte in virtuellen Räumen rezipiert, reflektiert und didaktisch gerahmt werden können. Die Ergebnisse zeigen Rezeptionsmodi zwischen affektiver Nähe, verkörperter Handlung und reflexiver Distanz. Während Goethe VR auf Grundlage des Dramentextes explorative Handlungs-Spiel-Räume eröffnet, fungiert die Anne Frank House VR in der Reflexion des Tagebuchs als kontemplativer Resonanzraum erinnerungskultureller Empathie.
Auf dieser Basis wird das Konzept der Literatur-Begehung entwickelt – als körperlichräumlich gebundene Rezeption, die immersive Erfahrungen mit emotionaler Involvierung und didaktischer Reflexion verbindet.
Abstract (english):
Virtual reality (VR) opens up new perspectives for literary and media education in German language teaching—as an aesthetic and situational space for experience, a medium for narrative participation, and a didactic challenge. This article presents two exploratory studies: a qualitative investigation of Goethe VR, in which students experience Goethe’s Faust immersively from the perspective of the main character Faust, and a survey of the documentary-style Anne Frank House VR, which focuses on the subjective experience of presence in a historical space of remembrance and enriches it with quotations from Anne Frank’s diary.
The focus is on the question of how canonical texts can be received, reflected upon, and didactically framed in virtual spaces. The results show modes of reception ranging from affective closeness to embodied action and reflexive distance. While Goethe VR opens up exploratory spaces for action and play based on the drama text, Anne Frank House VR functions as a contemplative resonance space for empathy in memory culture in its reflection on the diary.
On this basis, the concept of literary exploration is developed—as a physically and spatially bound reception that combines immersive experiences with emotional involvement and didactic reflection.
Ziel dieser quantitativen Studie ist es, die Korrelation zwischen den L2-Lernstrategien von Deutschlernenden und der Beherrschung der Nebensatzsyntax bei deutschen Verben festzustellen. Zur Messung der Lernstrategien wurde die Version 7 des Oxford SILL (Oxford, 2003) verwendet. Die Forced-Choice-Tests von Catasso (2004) wurden verwendet, um die Kenntnisse der Nebensatzsyntax zu beurteilen. Die Probanden an dieser Studie waren 55 Schüler einer deutschen Schule Chiles. Die mit R durchgeführte Analyse zeigt, dass die am häufigsten verwendete Lernstrategie die Kompensationsstrategien waren. Die Daten zeigten, dass keine statistisch signifikante positive Korrelation zwischen häufiger Lernstrategieanwendung und besserer Beherrschung der Verbstellung besteht. Es besteht jedoch eine statistisch signifikante negative Korrelation zwischen dem Einsatz metakognitiver Strategien und der Beherrschung der Nebensatzsyntax bei männlichen Lernenden. Die persönlichen Variablen beim Sprachenlernen könnten positive Auswirkungen haben. In Zukunft wäre es sinnvoll, diese Art von Korrelationsstudien auf andere Aspekte des deutschen Spracherwerbs wie die Deklination auszuweiten.
German literature, Germanic languages. Scandinavian languages
This contribution discusses the problem of the allegedly ‘irregular’ strong verbs in Dutch, being a plea for correct terminological use in grammar. Strong verbs belong to the basic vocabulary of Dutch, being mostly verbs that concern everyday life such as eating, sleeping and walking. They have a regular structure and the label ‘irregular’ makes the average second language learner automatically think ‘oh, this must be difficult’. First, this contribution examines how Dutch linguists have looked at strong verbs over the centuries. Then, the presentation of strong verbs in recent linguistic and pedagogical works will be discussed to come finally to a conclusion and to some proposals.
Michel Steuwer, Thomas Koehler, Bastian Köpcke
et al.
The trend towards specialization of software and hardware - fuelled by the end of Moore's law and the still accelerating interest in domain-specific computing, such as machine learning - forces us to radically rethink our compiler designs. The era of a universal compiler framework built around a single one-size-fits-all intermediate representation (IR) is over. This realization has sparked the creation of the MLIR compiler framework that empowers compiler engineers to design and integrate IRs capturing specific abstractions. MLIR provides a generic framework for SSA-based IRs, but it doesn't help us to decide how we should design IRs that are easy to develop, to work with and to combine into working compilers. To address the challenge of IR design, we advocate for a language-oriented compiler design that understands IRs as formal programming languages and enforces their correct use via an accompanying type system. We argue that programming language techniques directly guide extensible IR designs and provide a formal framework to reason about transforming between multiple IRs. In this paper, we discuss the design of the Shine compiler that compiles the high-level functional pattern-based data-parallel language RISE via a hybrid functional-imperative intermediate language to C, OpenCL, and OpenMP. We compare our work directly with the closely related pattern-based Lift IR and compiler. We demonstrate that our language-oriented compiler design results in a more robust and predictable compiler that is extensible at various abstraction levels. Our experimental evaluation shows that this compiler design is able to generate high-performance GPU code.
Although the notion of qualified names is popular in module systems, it causes severe complications. In this paper, we propose an alternative to qualified names. The key idea is to import the declarations in other modules to the current module before they are used. In this way, all the declarations can be accessed locally. However, this approach is not efficient in memory usage. Our contribution is the {\it module weakening} scheme which allows us to import the minimal parts. As an example of this approach, we propose a module system for functional languages.
Das mediendidaktische Konzept des Lernpfads wird als computergestützte, auf Selbststeuerung ausgerichtete Lernumgebung beschrieben, die aus einer sinnvollen Abfolge von Aufgaben besteht. Daraus ergibt sich ein Zusammenspiel von Selbst- und Fremdsteuerung, das im vorliegenden Beitrag näher untersucht wird, indem Merkmale selbstgesteuerter Lernumgebungen und Aufgabenmerkmale, die im Konzept begründet liegen, herausgearbeitet werden. Auf dieser Basis kann das Potenzial des Konzepts für den Deutschunterricht diskutiert und an einem Praxisbeispiel veranschaulicht werden. Bei diesem handelt es sich um einen komplexen Lernpfad, der für die 9. Klasse eines Gymnasiums entworfen worden ist. Die Schüler*innen finden in dieser Lernumgebung eigene Pfade, um das mündliche Argumentieren zu üben.
Abstract (english): Finding your own path. „Learning pathes“ as self-regulated learning environments
The concept of “Lernpfad” is described as computer supported learning environment that consists in a sequence of tasks and aims at self-regulated learning. In order to assess this concept this paper refers to characteristics that are used to describe tasks and self-regulated learning environments. Based on this analysis it is possible to discuss the concept‘s potential for German classes. The introduction of an example is used to illustrate the concept. This example is constructed to provide opportunities for students in grade 9 of the Gymnasium to practice debating as an oral competence.
Formålet med studien som presenteres i denne artikkelen, er å kartlegge bruksområdene og funksjonene til norske demonstrativkonstruksjoner som er bygd opp av et “grunndemonstrativ”, f.eks. den, denne, hun og han, og en forsterker, f.eks. her eller derre. Videre er målet å drøfte utviklinga av disse demonstrativene i lys av modeller om forsterkingssykluser og paradigmatisk konkurranse. Datagrunnlaget for analysen er hovedsakelig autentiske talte ytringer fra Nordisk dialektkorpus, samt skriftlige historiske dokumenter fra bl.a. Diplomatarium Norvegicum. Det argumenteres for at de nydanna komplekse demonstrativene i norsk har spesialiserte pragmatiske funksjoner, henholdsvis eksoforisk deiksis og bakgrunns-deiktisk funksjon. Syklisk forsterking av demonstrativer har fellestrekk med forsterking av nektingsuttrykk, og den paradigmatiske konkurransen som oppstår ved forsterking, kan føre til katalysering av grammatikaliseringa av gamle demonstrativer/ nektingsuttrykk. I motsetning til hva som noen ganger har vært hevda i litteraturen om demonstrativer, er grammatikalisering dermed et resultat av snarere enn årsak til forsterking.
Philology. Linguistics, Germanic languages. Scandinavian languages
The projected language of a general deterministic automaton with $n$ states is recognizable by a deterministic automaton with $2^{n-1} + 2^{n-m} - 1$ states, where $m$ denotes the number of states incident to unobservable non-loop transitions, and this bound is best possible. Here, we derive the tight bound $2^{n - \lceil \frac{m}{2} \rceil} - 1$ for permutation automata. For a state-partition automaton with $n$ states (also called automata with the observer property) the projected language is recognizable with $n$ states. Up to now, these, and finite languages projected onto unary languages, were the only classes of automata known to possess this property. We show that this is also true for commutative automata and we find commutative automata that are not state-partition automata.
There are tools to ease the 2D/3D graphics development for programmers. Sometimes, these are not directly accessible for all users requiring commercial licenses or based on trials, or long learning periods before to use them. In the modern world, the time to release final programs is crucial for the company successfully, also for saving money. Then, if programmers can handle tools to minimize the development time using well-known programming languages, they can deliver final programs on time, with minimum effort. This concept is the goal of this paper, offering a tool to create 3D renders over a familiarize programming language to speed up the web development time process. We present an extension of an interpreted programming language with an easy syntax to display 3D graphics on the web generating a template in a well-known web programming language, which can be customized and extended. Our proposal is based on Lua programming language as the input language for programmers, offering a web editor which interprets its syntax and exporting templates in WebGL over Javascript, also getting immediate output in a web browser. Tests show the effectiveness of our approach focus on the written code lines, also getting the expected output using a few computational resources.
Jan Baumeister, Bernd Finkbeiner, Matthis Kruse
et al.
Runtime monitors that are specified in a stream-based monitoring language tend to be easier to understand, maintain, and reuse than those written in a standard programming language. Because of their formal semantics, such specification languages are also a natural choice for safety-critical applications. Unlike for standard programming languages, there is, however, so far very little support for automatic code optimization. In this paper, we present the first collection of code transformations for the stream-based monitoring language RTLola. We show that classic compiler optimizations, such as Sparse Conditional Constant Propagation and Common Subexpression Elimination, can be adapted to monitoring specifications. We also develop new transformations -- Pacing Type Refinement and Filter Refinement -- which exploit the specific modular structure of RTLola as well as the implementation freedom afforded by a declarative specification language. We demonstrate the significant impact of the code transformations on benchmarks from the monitoring of unmanned aircraft systems (UAS).
Marie-Anne Lachaux, Baptiste Roziere, Lowik Chanussot
et al.
A transcompiler, also known as source-to-source translator, is a system that converts source code from a high-level programming language (such as C++ or Python) to another. Transcompilers are primarily used for interoperability, and to port codebases written in an obsolete or deprecated language (e.g. COBOL, Python 2) to a modern one. They typically rely on handcrafted rewrite rules, applied to the source code abstract syntax tree. Unfortunately, the resulting translations often lack readability, fail to respect the target language conventions, and require manual modifications in order to work properly. The overall translation process is timeconsuming and requires expertise in both the source and target languages, making code-translation projects expensive. Although neural models significantly outperform their rule-based counterparts in the context of natural language translation, their applications to transcompilation have been limited due to the scarcity of parallel data in this domain. In this paper, we propose to leverage recent approaches in unsupervised machine translation to train a fully unsupervised neural transcompiler. We train our model on source code from open source GitHub projects, and show that it can translate functions between C++, Java, and Python with high accuracy. Our method relies exclusively on monolingual source code, requires no expertise in the source or target languages, and can easily be generalized to other programming languages. We also build and release a test set composed of 852 parallel functions, along with unit tests to check the correctness of translations. We show that our model outperforms rule-based commercial baselines by a significant margin.
Drivers are written in C or restricted subsets of C++ on all production-grade server, desktop, and mobile operating systems. They account for 66% of the code in Linux, but 39 out of 40 security bugs related to memory safety found in Linux in 2017 are located in drivers. These bugs could have been prevented by using high-level languages for drivers. We present user space drivers for the Intel ixgbe 10 Gbit/s network cards implemented in Rust, Go, C#, Java, OCaml, Haskell, Swift, JavaScript, and Python written from scratch in idiomatic style for the respective languages. We quantify costs and benefits of using these languages: High-level languages are safer (fewer bugs, more safety checks), but run-time safety checks reduce throughput and garbage collection leads to latency spikes. Out-of-order CPUs mitigate the cost of safety checks: Our Rust driver executes 63% more instructions per packet but is only 4% slower than a reference C implementation. Go's garbage collector keeps latencies below 100 $μ$s even under heavy load. Other languages fare worse, but their unique properties make for an interesting case study. All implementations are available as free and open source at https://github.com/ixy-languages/ixy-languages.
In previous studies on learner lexicography, design features of both the content and presentation of learner's dictionaries are the two major research concerns. The quality assessment of learner's dictionaries also covers the two dimensions. Terms used for evaluating them are respectively "usability" or "availability" for the former and "findability" or "accessibility" for the latter. However, the lexicographical construction of "learnability", which takes into account the users' reference and learning needs, remains virtually unexplored either theoretically or practically. Compared to the features of dictionary design mentioned above, "learnability" as the design philosophy of learner lexicography is worth more serious consideration. The present paper aims at exploring the lexicographical notion of "learnability" by way of introducing the neglected legacy of Robert Morrison in his compilation of Wuche Yunfu (五车韵府) (1819), which is characterized by a high degree of learnability illustrated in the dictionary entries. Morrison's pioneering efforts may help with the conceptual clarification of "learnability" in compiling learner's dictionaries, bilingual ones in particular. Moreover, it is hoped that the recognition of Morrison's lexicographical practice will be beneficial to the future production of better Chinese–English dictionaries for non-native Chinese learners.
Philology. Linguistics, Languages and literature of Eastern Asia, Africa, Oceania
Formal models of games help us account for and predict behavior, leading to more robust and innovative designs. While the games research community has proposed many formalisms for both the "game half" (game models, game description languages) and the "human half" (player modeling) of a game experience, little attention has been paid to the interface between the two, particularly where it concerns the player expressing her intent toward the game. We describe an analytical and computational toolbox based on programming language theory to examine the phenomenon sitting between control schemes and game rules, which we identify as a distinct player intent language for each game.
Reversible forms of computations are often interesting from an energy efficiency point of view. When the computation device in question is an automaton, it is known that the minimal reversible automaton recognizing a given language is not necessarily unique, moreover, there are languages having arbitrarily large reversible recognizers possessing no nontrivial reversible congruence. However, the exact characterization of this class of languages was open. In this paper we give a forbidden pattern capturing the reversible regular languages having only finitely many reduced reversible automata, allowing an efficient (NL) decision procedure.