Algebraic Effect Handlers Go Mainstream
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“Scrap Your Boilerplate” Reloaded
“Scrap Your Boilerplate” Reloaded Ralf Hinze1, Andres L¨oh1, and Bruno C. d. S. Oliveira2 1 Institut f¨urInformatik III, Universit¨atBonn R¨omerstraße164, 53117 Bonn, Germany {ralf,loeh}@informatik.uni-bonn.de 2 Oxford University Computing Laboratory Wolfson Building, Parks Road, Oxford OX1 3QD, UK [email protected] Abstract. The paper “Scrap your boilerplate” (SYB) introduces a com- binator library for generic programming that offers generic traversals and queries. Classically, support for generic programming consists of two es- sential ingredients: a way to write (type-)overloaded functions, and in- dependently, a way to access the structure of data types. SYB seems to lack the second. As a consequence, it is difficult to compare with other approaches such as PolyP or Generic Haskell. In this paper we reveal the structural view that SYB builds upon. This allows us to define the combinators as generic functions in the classical sense. We explain the SYB approach in this changed setting from ground up, and use the un- derstanding gained to relate it to other generic programming approaches. Furthermore, we show that the SYB view is applicable to a very large class of data types, including generalized algebraic data types. 1 Introduction The paper “Scrap your boilerplate” (SYB) [1] introduces a combinator library for generic programming that offers generic traversals and queries. Classically, support for generic programming consists of two essential ingredients: a way to write (type-)overloaded functions, and independently, a way to access the structure of data types. SYB seems to lacks the second, because it is entirely based on combinators. -
Manydsl One Host for All Language Needs
ManyDSL One Host for All Language Needs Piotr Danilewski March 2017 A dissertation submitted towards the degree (Dr.-Ing.) of the Faculty of Mathematics and Computer Science of Saarland University. Saarbrücken Dean Prof. Dr. Frank-Olaf Schreyer Date of Colloquium June 6, 2017 Examination Board: Chairman Prof. Dr. Sebastian Hack Reviewers Prof. Dr.-Ing. Philipp Slusallek Prof. Dr. Wilhelm Reinhard Scientific Asistant Dr. Tim Dahmen Piotr Danilewski, [email protected] Saarbrücken, June 6, 2017 Statement I hereby declare that this dissertation is my own original work except where otherwise indicated. All data or concepts drawn directly or indirectly from other sources have been correctly acknowledged. This dissertation has not been submitted in its present or similar form to any other academic institution either in Germany or abroad for the award of any degree. Saarbrücken, June 6, 2017 (Piotr Danilewski) Declaration of Consent Herewith I agree that my thesis will be made available through the library of the Computer Science Department. Saarbrücken, June 6, 2017 (Piotr Danilewski) Zusammenfassung Die Sprachen prägen die Denkweise. Das ist die Tatsache für die gesprochenen Sprachen aber auch für die Programmiersprachen. Da die Computer immer wichtiger in jedem Aspekt des menschlichen Lebens sind, steigt der Bedarf um entsprechend neue Konzepte in den Programmiersprachen auszudrücken. Jedoch, damit unsere Denkweise sich weiterentwicklen könnte, müssen sich auch die Programmiersprachen weiterentwickeln. Aber welche Hilfsmittel gibt es um die Programmiersprachen zu schaffen und aufzurüsten? Wie kann man Entwickler ermutigen damit sie eigene Sprachen definieren, die dem Bereich in dem sie arbeiten am besten passen? Heutzutage gibt es zwei Methoden. -
A Type and Scope Safe Universe of Syntaxes with Binding: Their Semantics and Proofs
ZU064-05-FPR jfp19 26 March 2020 16:6 Under consideration for publication in J. Functional Programming 1 A Type and Scope Safe Universe of Syntaxes with Binding: Their Semantics and Proofs GUILLAUME ALLAIS, ROBERT ATKEY University of Strathclyde (UK) JAMES CHAPMAN Input Output HK Ltd. (HK) CONOR MCBRIDE University of Strathclyde (UK) JAMES MCKINNA University of Edinburgh (UK) Abstract Almost every programming language’s syntax includes a notion of binder and corresponding bound occurrences, along with the accompanying notions of α-equivalence, capture-avoiding substitution, typing contexts, runtime environments, and so on. In the past, implementing and reasoning about programming languages required careful handling to maintain the correct behaviour of bound variables. Modern programming languages include features that enable constraints like scope safety to be expressed in types. Nevertheless, the programmer is still forced to write the same boilerplate over again for each new implementation of a scope safe operation (e.g., renaming, substitution, desugaring, printing, etc.), and then again for correctness proofs. We present1 an expressive universe of syntaxes with binding and demonstrate how to (1) implement scope safe traversals once and for all by generic programming; and (2) how to derive properties of these traversals by generic proving. Our universe description, generic traversals and proofs, and our examples have all been formalised in Agda and are available in the accompanying material available online at https://github.com/gallais/generic-syntax. 1 Introduction In modern typed programming languages, programmers writing embedded DSLs (Hudak (1996)) and researchers formalising them can now use the host language’s type system to help them. -
On Specifying and Visualising Long-Running Empirical Studies
On Specifying and Visualising Long-Running Empirical Studies Peter Y. H. Wong and Jeremy Gibbons Computing Laboratory, University of Oxford, United Kingdom fpeter.wong,[email protected] Abstract. We describe a graphical approach to formally specifying tem- porally ordered activity routines designed for calendar scheduling. We introduce a workflow model OWorkflow, for constructing specifications of long running empirical studies such as clinical trials in which obser- vations for gathering data are performed at strict specific times. These observations, either manually performed or automated, are often inter- leaved with scientific procedures, and their descriptions are recorded in a calendar for scheduling and monitoring to ensure each observation is carried out correctly at a specific time. We also describe a bidirectional transformation between OWorkflow and a subset of Business Process Modelling Notation (BPMN), by which graphical specification, simula- tion, automation and formalisation are made possible. 1 Introduction A typical long-running empirical study consists of a series of scientific proce- dures interleaved with a set of observations performed over a period of time; these observations may be manually performed or automated, and are usually recorded in a calendar schedule. An example of a long-running empirical study is a clinical trial, where observations, specifically case report form submissions, are performed at specific points in the trial. In such examples, observations are interleaved with clinical interventions on patients; precise descriptions of these observations are then recorded in a patient study calendar similar to the one shown in Figure 1(a). Currently study planners such as trial designers supply information about observations either textually or by inputting textual infor- mation and selecting options on XML-based data entry forms [2], similar to the one shown in Figure 1(b). -
Agda User Manual Release 2.6.3
Agda User Manual Release 2.6.3 The Agda Team Sep 23, 2021 Contents 1 Overview 3 2 Getting Started 5 2.1 What is Agda?..............................................5 2.2 Installation................................................7 2.3 ‘Hello world’ in Agda.......................................... 13 2.4 A Taste of Agda............................................. 14 2.5 A List of Tutorials............................................ 22 3 Language Reference 25 3.1 Abstract definitions............................................ 25 3.2 Built-ins................................................. 27 3.3 Coinduction............................................... 40 3.4 Copatterns................................................ 42 3.5 Core language.............................................. 45 3.6 Coverage Checking............................................ 48 3.7 Cubical.................................................. 51 3.8 Cumulativity............................................... 65 3.9 Data Types................................................ 66 3.10 Flat Modality............................................... 69 3.11 Foreign Function Interface........................................ 70 3.12 Function Definitions........................................... 75 3.13 Function Types.............................................. 78 3.14 Generalization of Declared Variables.................................. 79 3.15 Guarded Cubical............................................. 84 3.16 Implicit Arguments........................................... -
Lecture Notes in Computer Science 6120 Commenced Publication in 1973 Founding and Former Series Editors: Gerhard Goos, Juris Hartmanis, and Jan Van Leeuwen
Lecture Notes in Computer Science 6120 Commenced Publication in 1973 Founding and Former Series Editors: Gerhard Goos, Juris Hartmanis, and Jan van Leeuwen Editorial Board David Hutchison Lancaster University, UK Takeo Kanade Carnegie Mellon University, Pittsburgh, PA, USA Josef Kittler University of Surrey, Guildford, UK Jon M. Kleinberg Cornell University, Ithaca, NY, USA Alfred Kobsa University of California, Irvine, CA, USA Friedemann Mattern ETH Zurich, Switzerland John C. Mitchell Stanford University, CA, USA Moni Naor Weizmann Institute of Science, Rehovot, Israel Oscar Nierstrasz University of Bern, Switzerland C. Pandu Rangan Indian Institute of Technology, Madras, India Bernhard Steffen TU Dortmund University, Germany Madhu Sudan Microsoft Research, Cambridge, MA, USA Demetri Terzopoulos University of California, Los Angeles, CA, USA Doug Tygar University of California, Berkeley, CA, USA Gerhard Weikum Max-Planck Institute of Computer Science, Saarbruecken, Germany Claude Bolduc Jules Desharnais Béchir Ktari (Eds.) Mathematics of Program Construction 10th International Conference, MPC 2010 Québec City, Canada, June 21-23, 2010 Proceedings 13 Volume Editors Claude Bolduc Jules Desharnais Béchir Ktari Université Laval, Département d’informatique et de génie logiciel Pavillon Adrien-Pouliot, 1065 Avenue de la Médecine Québec, QC, G1V 0A6, Canada E-mail: {Claude.Bolduc, Jules.Desharnais, Bechir.Ktari}@ift.ulaval.ca Library of Congress Control Number: 2010927075 CR Subject Classification (1998): F.3, D.2, F.4.1, D.3, D.2.4, D.1 LNCS Sublibrary: SL 1 – Theoretical Computer Science and General Issues ISSN 0302-9743 ISBN-10 3-642-13320-7 Springer Berlin Heidelberg New York ISBN-13 978-3-642-13320-6 Springer Berlin Heidelberg New York This work is subject to copyright. -
Current Issue of FACS FACTS
Issue 2021-2 July 2021 FACS A C T S The Newsletter of the Formal Aspects of Computing Science (FACS) Specialist Group ISSN 0950-1231 FACS FACTS Issue 2021-2 July 2021 About FACS FACTS FACS FACTS (ISSN: 0950-1231) is the newsletter of the BCS Specialist Group on Formal Aspects of Computing Science (FACS). FACS FACTS is distributed in electronic form to all FACS members. Submissions to FACS FACTS are always welcome. Please visit the newsletter area of the BCS FACS website for further details at: https://www.bcs.org/membership/member-communities/facs-formal-aspects- of-computing-science-group/newsletters/ Back issues of FACS FACTS are available for download from: https://www.bcs.org/membership/member-communities/facs-formal-aspects- of-computing-science-group/newsletters/back-issues-of-facs-facts/ The FACS FACTS Team Newsletter Editors Tim Denvir [email protected] Brian Monahan [email protected] Editorial Team: Jonathan Bowen, John Cooke, Tim Denvir, Brian Monahan, Margaret West. Contributors to this issue: Jonathan Bowen, Andrew Johnstone, Keith Lines, Brian Monahan, John Tucker, Glynn Winskel BCS-FACS websites BCS: http://www.bcs-facs.org LinkedIn: https://www.linkedin.com/groups/2427579/ Facebook: http://www.facebook.com/pages/BCS-FACS/120243984688255 Wikipedia: http://en.wikipedia.org/wiki/BCS-FACS If you have any questions about BCS-FACS, please send these to Jonathan Bowen at [email protected]. 2 FACS FACTS Issue 2021-2 July 2021 Editorial Dear readers, Welcome to the 2021-2 issue of the FACS FACTS Newsletter. A theme for this issue is suggested by the thought that it is just over 50 years since the birth of Domain Theory1. -
Objective Metatheory of Cubical Type Theories (Thesis Proposal) Jonathan Sterling August 15, 2020
Objective Metatheory of Cubical Type Theories (thesis proposal) Jonathan Sterling August 15, 2020 School of Computer Science Carnegie Mellon University Pittsburgh, PA 15213 Thesis Committee: Robert Harper, Chair Lars Birkedal Jeremy Avigad Karl Crary Favonia Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy. Copyright © 2020 Jonathan Sterling I gratefully acknowledge the support of the Air Force Office of Scientific Research through MURI grant FA9550-15-1-0053. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the AFOSR. Contents 1 Introduction 1 1.1 Computation in dependent type theory ................. 1 1.2 Syntactic, phenomenal, and semantic aspects of equality . 3 1.3 Subjective metatheory: the mathematics of formalisms . 6 1.4 Objective metatheory: a syntax-invariant perspective . 6 1.5 Towards principled implementation of proof assistants . 20 1.6 Thesis Statement ............................. 20 1.7 Acknowledgments ............................. 21 2 Background and Prior Work 23 2.1 RedPRL: a program logic for cubical type theory . 23 2.2 The redtt proof assistant ......................... 28 2.3 XTT: cubical equality and gluing .................... 39 3 Proposed work 45 3.1 Algebraic model theory .......................... 46 3.2 Contexts and injective renamings .................... 46 3.3 Characterizing normal forms ....................... 48 3.4 Normalization of cartesian cubical type theory . 49 3.5 redtt reloaded: abstract elaboration ................... 50 3.6 Timeline and fallback positions ..................... 50 A redtt: supplementary materials 51 A.1 The RTT core language ......................... 51 A.2 Normalization by evaluation for RTT . 59 A.3 Elaboration relative to a boundary .................. -
Haskell Communities and Activities Report
Haskell Communities and Activities Report http://www.haskell.org/communities/ Eighth Edition – May 13, 2005 Andres L¨oh (ed.) Perry Alexander Lloyd Allison Tiago Miguel Laureano Alves Krasimir Angelov Alistair Bayley J´er´emy Bobbio Bj¨orn Bringert Niklas Broberg Paul Callaghan Mark Carroll Manuel Chakravarty Olaf Chitil Koen Claessen Catarina Coquand Duncan Coutts Philippa Cowderoy Alain Cr´emieux Iavor Diatchki Atze Dijkstra Shae Erisson Sander Evers Markus Forsberg Simon Foster Leif Frenzel Andr´eFurtado John Goerzen Murray Gross Walter Gussmann Jurriaan Hage Sven Moritz Hallberg Thomas Hallgren Keith Hanna Bastiaan Heeren Anders H¨ockersten John Hughes Graham Hutton Patrik Jansson Johan Jeuring Paul Johnson Isaac Jones Oleg Kiselyov Graham Klyne Daan Leijen Huiqing Li Andres L¨oh Rita Loogen Salvador Lucas Christoph Luth¨ Ketil Z. Malde Christian Maeder Simon Marlow Conor McBride John Meacham Serge Mechveliani Neil Mitchell William Garret Mitchener Andy Moran Matthew Naylor Rickard Nilsson Jan Henry Nystr¨om Sven Panne Ross Paterson Jens Petersen John Peterson Simon Peyton-Jones Jorge Sousa Pinto Bernie Pope Claus Reinke Frank Rosemeier David Roundy George Russell Chris Ryder David Sabel Uwe Schmidt Martijn Schrage Peter Simons Anthony Sloane Dominic Steinitz Donald Bruce Stewart Martin Sulzmann Autrijus Tang Henning Thielemann Peter Thiemann Simon Thompson Phil Trinder Arjan van IJzendoorn Tuomo Valkonen Eelco Visser Joost Visser Malcolm Wallace Ashley Yakeley Jory van Zessen Bulat Ziganshin Preface You are reading the 8th edition of the Haskell Communities and Activities Report (HCAR). These are interesting times to be a Haskell enthusiast. Everyone seems to be talking about darcs (→ 6.3) and Pugs (→ 6.1) these days, and it is nice to see Haskell being mentioned in places where it usually was not. -
162581776.Pdf
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by The IT University of Copenhagen's Repository Verification of High-Level Transformations with Inductive Refinement Types Ahmad Salim Al-Sibahi Thomas P. Jensen DIKU/Skanned.com/ITU INRIA Rennes Denmark France Aleksandar S. Dimovski Andrzej Wąsowski ITU/Mother Teresa University, Skopje ITU Denmark/Macedonia Denmark Abstract 1 Introduction High-level transformation languages like Rascal include ex- Transformations play a central role in software development. pressive features for manipulating large abstract syntax trees: They are used, amongst others, for desugaring, model trans- first-class traversals, expressive pattern matching, backtrack- formations, refactoring, and code generation. The artifacts ing and generalized iterators. We present the design and involved in transformations—e.g., structured data, domain- implementation of an abstract interpretation tool, Rabit, for specific models, and code—often have large abstract syn- verifying inductive type and shape properties for transfor- tax, spanning hundreds of syntactic elements, and a corre- mations written in such languages. We describe how to per- spondingly rich semantics. Thus, writing transformations form abstract interpretation based on operational semantics, is a tedious and error-prone process. Specialized languages specifically focusing on the challenges arising when analyz- and frameworks with high-level features have been devel- ing the expressive traversals and pattern matching. Finally, oped to address this challenge of writing and maintain- we evaluate Rabit on a series of transformations (normaliza- ing transformations. These languages include Rascal [28], tion, desugaring, refactoring, code generators, type inference, Stratego/XT [12], TXL [16], Uniplate [31] for Haskell, and etc.) showing that we can effectively verify stated properties. -
Domain-Specific Languages for Modeling and Simulation
Domain-specifc Languages for Modeling and Simulation Dissertation zur Erlangung des akademischen Grades Doktor-Ingenieur (Dr.-Ing.) der Fakultät für Informatik und Elektrotechnik der Universität Rostock vorgelegt von Tom Warnke, geb. am 25.01.1988 in Malchin aus Rostock Rostock, 14. September 2020 https://doi.org/10.18453/rosdok_id00002966 Dieses Werk ist lizenziert unter einer Creative Commons Namensnennung - Weitergabe unter gleichen Bedingungen 4.0 International Lizenz. Gutachter: Prof. Dr. Adelinde M. Uhrmacher (Universität Rostock) Prof. Rocco De Nicola (IMT Lucca) Prof. Hans Vangheluwe (Universität Antwerpen) Eingereicht am 14. September 2020 Verteidigt am 8. Januar 2021 Abstract Simulation models and simulation experiments are increasingly complex. One way to handle this complexity is developing software languages tailored to specifc application domains, so-called domain-specifc languages (DSLs). This thesis explores the potential of employing DSLs in modeling and simulation. We study diferent DSL design and implementation techniques and illustrate their benefts for expressing simulation models as well as simulation experiments with several examples. Regarding simulation models, we focus on discrete-event models based on continuous- time Markov chains (CTMCs). Most of our work revolves around ML-Rules, an rule-based modeling language for biochemical reaction networks. First, we relate the expressive power of ML-Rules to other currently available modeling languages for this application domain. Then we defne the abstract syntax and operational semantics for ML-Rules, mapping models to CTMCs in an unambiguous and precise way. Based on the formal defnitions, we present two approaches to implement ML-Rules as a DSL. The core of both implementations is fnding the matches for the patterns on the left side of ML-Rules’ rules. -
Unbounded Spigot Algorithms for the Digits of Pi
Unbounded Spigot Algorithms for the Digits of Pi Jeremy Gibbons 1 INTRODUCTION. Rabinowitz and Wagon [8] present a “remarkable” algorithm for com- puting the decimal digits of π, based on the expansion ∞ (i!)22i+1 π = ∑ . (1) i=0 (2i + 1)! Their algorithm uses only bounded integer arithmetic, and is surprisingly efficient. Moreover, it admits extremely concise implementations. Witness, for example, the following (deliberately obfuscated) C pro- gram due to Dik Winter and Achim Flammenkamp [1, p. 37], which produces the first 15,000 decimal digits of π: a[52514],b,c=52514,d,e,f=1e4,g,h;main(){for(;b=c-=14;h=printf("%04d", e+d/f))for(e=d%=f;g=--b*2;d/=g)d=d*b+f*(h?a[b]:f/5),a[b]=d%--g;} Rabinowitz and Wagon call their algorithm a spigot algorithm, because it yields digits incrementally and does not reuse digits after they have been computed. The digits drip out one by one, as if from a leaky tap. In contrast, most algorithms for computing the digits of π execute inscrutably, delivering no output until the whole computation is completed. However, the Rabinowitz–Wagon algorithm has its weaknesses. In particular, the computation is in- herently bounded: one has to commit in advance to computing a certain number of digits. Based on this commitment, the computation proceeds on an appropriate finite prefix of the infinite series (1). In fact, it is essentially impossible to determine in advance how big that finite prefix should be for a given number of digits—specifically, a computation that terminates with nines for the last few digits of the output is inconclusive, because there may be a “carry” from the first few truncated terms.