WITS 2022 is the first Workshop on the Implementation of Type Systems. The workshop will be held on January 22, 2022, in Philadelphia, PA, United States, co-located with POPL. The goal of this workshop is to bring together the implementors of a variety of languages with advanced type systems. The main focus is on the practical issues that come up in the implementation of these systems, rather than the theoretical frameworks that underlie them. In particular, we want to encourage exchanging ideas between the communities around specific systems that would otherwise be accessible to only a very select group.
Given the importance of collaboration among the attendees at WITS, if circumstances around covid-19 force POPL (and its co-located events) to go virtual, WITS will be deferred until a time when we can come together safely in person.
The workshop will have a mix of invited and contributed talks, organized discussion times, and informal collaboration time.
Scope
We invite participants to share their experiences, study differences among the implementations, and generalize lessons from those. We also want to promote the creation of a shared vocabulary and set of best practices for implementing type systems.
Here are a few examples of topics we are interested to discuss:
- syntax with binders and substitution
- conversion modulo beta and eta
- implicit arguments and metavariables
- unification and constraint solving
- metaprogramming and tactic languages
- editor integration and automation
- discoverability of language features
- pretty printing and error messages
This list is not exhaustive, so please contact the PC chairs in case you are unsure if a topic falls within the scope of the workshop.
Important Dates
- Abstract submission deadline: 16 November, 2021 (AoE)
- Notification: 1 December, 2021 (AoE)
- Workshop in Philadelphia: 22 January, 2022
Attendance and registration
WITS 2022 is colocated with POPL 2022 in Philadelphia, USA. More information on registration and attendance will be announced later.
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10:20 - 12:00 | Session 2WITS at Salon III | ||
10:20 45m Keynote | Make Three To Throw Away: Frontiers in Homotopical Proof AssistantsRemote WITS Jonathan Sterling Aarhus University | ||
11:05 15m Talk | The curious case of case: correct & efficient representation of case analysis in Coq and MetaCoqRemote WITS Matthieu Sozeau Inria, Meven Lennon-Bertrand Inria – LS2N, Université de Nantes, Yannick Forster Inria | ||
11:20 40m Other | Elaborator reflection APIs (discussion)Remote WITS Jesper Cockx TU Delft | ||
11:20 40m Other | Invisible arguments: language design (discussion)In-Person WITS Richard A. Eisenberg Tweag | ||
13:30 - 14:45 | Session 3WITS at Salon III | ||
13:30 15m Talk | Tries that matchRemote WITS Sebastian Graf Karlsruhe Institute of Technology | ||
13:45 15m Talk | Gotta prove fast: building an ecosystem for effortless native compilation of tacticsRemote WITS Sebastian Ullrich Karlsruhe Institute of Technology | ||
14:00 45m Other | Benchmarking Binding (discussion)In-Person WITS Stephanie Weirich University of Pennsylvania | ||
14:00 45m Other | Fancy module systems (discussion)Remote WITS Jesper Cockx TU Delft | ||
15:05 - 16:20 | Session 4WITS at Salon III | ||
15:05 15m Talk | mitten: A Flexible Multimodal Proof AssistantRemote WITS Philipp Stassen Aarhus University, Daniel Gratzer Aarhus University, Lars Birkedal Aarhus University | ||
15:20 15m Talk | Understandable and Useful Error Messages for Liquid TypesRemote WITS Alcides Fonseca LASIGE, Faculdade de Ciências da Universidade de Lisboa, Catarina Gamboa LASIGE, Faculdade de Ciências da Universidade de Lisboa, João David LASIGE, Faculdade de Ciências da Universidade de Lisboa, Guilherme Espada LASIGE, Faculdade de Ciências da Universidade de Lisboa, Paulo Canelas LASIGE, Faculdade de Ciências da Universidade de Lisboa | ||
15:35 15m Talk | Deciding type equivalence with simple grammarsIn-Person WITS Bernardo Almeida LASIGE, Faculty of Sciences, University of Lisbon, Andreia Mordido Lasige / Faculty of Sciences, Universidade de Lisboa, Vasco T. Vasconcelos LASIGE, Faculty of Sciences, University of Lisbon | ||
15:50 15m Talk | Typechecking up to CongruenceIn-Person WITS Jad Elkhaleq Ghalayini University of Cambridge | ||
16:05 15m Talk | À bas l’η — Coq’s troublesome η-conversionRemote WITS Meven Lennon-Bertrand Inria – LS2N, Université de Nantes | ||
16:40 - 17:30 | Session 5WITS at Salon III | ||
16:40 15m Talk | Using Dependent Types at Scale: Maintaining the Agda Standard LibraryIn-Person WITS Matthew L. Daggitt Heriot-Watt University, Guillaume Allais University of St Andrews | ||
16:55 15m Talk | Setting the Record Straight with SingletonsRemote WITS Reed Mullanix University of Minnesota | ||
17:10 15m Talk | First-class pattern synonymsIn-Person WITS Tesla Zhang The Pennsylvania State University | ||
Accepted Presentations
Call for Contributions
WITS solicits two kinds of submissions:
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Contributed talks on the basis of an abstract. This can be on recently published or submitted work, work in progress, or even a project that is still in the idea phase.
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Proposals for roundtable discussions. This can be on any topic within the scope of the workshop, but should have a broader scope than a contributed talk. If accepted, you will be in charge of leading a discussion of 45 minutes around the proposed topic together with other interested attendees.
Both kinds of proposals should be accompanied by an abstract of max. 1 page (exclusive of references), formatted according to the guidelines for SIGPLAN conferences: use the sigplan option to the acmart LaTeX document class. WITS will have no published proceedings, so submitting to WITS does not interfere with submission (before, after, or simultaneously) with other venues.
WITS will be run as a hybrid (in-person and remote) workshop, using the infrastructure used to run a hybrid POPL. This page describes how WITS will play out in its hybrid incarnation. Jesper Cockx will be running the remote fork of WITS; Richard Eisenberg will be running the in-person fork.
First, read How to POPL, which describes how POPL talks will work in a hybrid setting. WITS will follow this format exactly: talks will be a mix of in-person and remote, where audiences both local and global will be able to hear, see, and ask questions. Events on the program are labeled Remote or In-Person depending on their status. (Events that have not yet been labeled are TBD.)
Like for POPL, all talks (in-person and remote) will be streamed on the SIGPLAN YouTube channel and will be made available on YouTube shortly after the workshop.
Discussions are harder to hybridize than talks, so each discussion will either be in-person or remote. Remote attendees can join only remote discussions. In-person attendees can join in-person discussions or, through the use of a headset and laptop, remote discussions.
On the day of WITS, there will be an opportunity to sign up to lead discussions on a topic of your choice. This opportunity will be presented both in-person and remotely. Local participants may choose to lead a remote discussion, if they wish to include remote participants.
In-person participants: please bring your laptop and charger. We’re hoping for opportunities to share code, talk about details, and trade implementation tricks. This works best with a laptop in front of you!
We are hoping to organize a WITS dinner after the workshop. If you will be attending in person and wish to join, please email Richard.