This is the artifact for the pearl paper "On Julia\u27s efficient algorithm for subtyping union types and covariant tuples.

Chung, Benjamin

Nardelli, Francesco Zappa

Vitek, Jan

English

Dagstuhl Research Online Publication Server

On Julia’s Efficient Algorithm for Subtyping UnionTypes and Covariant Tuples (Artifact)Benjamin ChungNortheastern University, Boston, MA, USAbchung@ccs.neu.eduFrancesco Zappa NardelliInria, Francefrancesco.zappa_nardelli@inria.frJan VitekNortheastern University, Boston, MA, USACzech Technical University in Prague, Czech Republicj.vitek@neu.eduAbstractThe key claim in our paper Julia’s efficientalgorithm for subtyping unions and covarianttuples is that our algorithm works. Thisartifact provides support for that claim throughtwo means: a Coq proof of the algorithm’scorrectness and an implementation of thealgorithm. The single-file proof contains threeproof-generating implementations of subtyping,based on normalization and two variations onthe subtyping algorithm we describe. Theimplementation consists of a web interface to anOCaml implementation of our algorithm, whichchecks subtyping between any two arbitrary user-defined types and generates both the answer anda trace of algorithm execution.2012 ACM Subject Classification Theory of computation → Type theory; Software and its engineering→ General programming languagesKeywords and phrases Type systems, subtyping, algorithmic type systems, distributive unionsDigital Object Identifier 10.4230/DARTS.5.2.8Related Article Benjamin Chung, Francesco Zappa Nardelli, and Jan Vitek, “Julia’s Efficient Algorithmfor Subtyping Unions and Covariant Tuples”, in 33rd European Conference on Object-OrientedProgramming (ECOOP 2019), LIPIcs, Vol. 134, pp. 24:1–24:15, 2019.https://dx.doi.org/10.4230/LIPIcs.ECOOP.2019.24Related Conference 33rd European Conference on Object-Oriented Programming (ECOOP 2019), July15–19, 2019, London, United Kingdom1 IntroductionThis is the artifact for the pearl paper “On Julia’s efficient algorithm for subtyping union typesand covariant tuples.” It consists of two primary components:index.html: An implementation of the subtyping algorithm running in a webpage. Thisimplementation is modified only slightly from the one described in the paper to enablevisualization. For sources, see the web-impl directory.julia-iterators.v: The Coq source code for the proofs referenced in our paper.This document is a worse-formatted and non-executable version of index.html. We suggestthe the online version (at https://benchung.github.io/subtype-artifact/) or simply openindex.html from the artifact archive for information on the artifact and to try out our algorithm.The website version of the artifact is tested to work in Google Chrome, and should work in allmodern browsers.© Benjamin W. Chung, Francesco Zappa Nardelli, and Jan Vitek;licensed under Creative Commons Attribution 3.0 Germany (CC BY 3.0 DE)Dagstuhl Artifacts Series, Vol. 5, Issue 2, Artifact No. 8, pp. 8:1–8:2Dagstuhl Artifacts SeriesSchloss Dagstuhl – Leibniz-Zentrum für Informatik, Dagstuhl Publishing, Germany8:2 On Julia’s Efficient Algorithm for Subtyping Union Types and Covariant Tuples (Artifact)2 ProofThe proof script (found in proof/julia-iterators.v) depends on Coq 8.9.0. A detailed de-scription of our proof can be found in section 3 of the paper. The proof is standalone, and hasno library dependencies.It relies on the standard library provided axiom Eqdep.Eq_rect_eq.eq_rect_eq, which es-tablishes the invariance under substitution of dependent equality. In our formalization, structuraltype iterators are dependent upon the type over which they iterate. We rely on this axiom todecide when two iterators are iterating over the same or different types. It is an axiom in oursystem as it is independent of the calculus of constructions.3 ImplementationWe include a web implementation of our algorithm. To use it, please see index.html for therunning implementation and instructions on its use and compilation.Compiling the ImplementationThe implementation is written in OCaml and compiled using js_of_ocaml. It requires:OCaml 4.07.0 or lateropam 2.0.4 or laterTo compile the OCaml to Javascript, runmake depsmakein the web-impl subdirectory, which should update the file web-impl/js/subtype.js.4 LicenseCopyright 2019 Benjamin Chung, Francesco Zappa Nardelli, Jan VitekThe artifact associated with this description is licensed under the Apache License, Version 2.0(the “License”); you may not use the associated artifact except in compliance with the License.You may obtain a copy of the License athttp://www.apache.org/licenses/LICENSE-2.0Unless required by applicable law or agreed to in writing, software distributed under theLicense is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONSOF ANY KIND, either express or implied. See the License for the specific language governingpermissions and limitations under the License.5 MD5 sum of the artifact4d0356d94cd8d21f42e6b73de886f8716 Size of the artifact746657 bytes

On Julia\u27s Efficient Algorithm for Subtyping Union Types and Covariant Tuples (Artifact)

https://drops.dagstuhl.de/opus/volltexte/2019/10785/pdf/DARTS-5-2-8.pdf

On Julia\u27s Efficient Algorithm for Subtyping Union Types and Covariant Tuples (Artifact)

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