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ICFP 2018
Sun 23 - Sat 29 September 2018 St. Louis, Missouri, United States

The Haskell Implementors’ Workshop is a forum for those involved in implementing Haskell systems, infrastructure, libraries and tools, for people generally involved in implementing Haskell technology. We share our work and discuss future directions and collaborations with others.

In 2018, the Haskell Implementors’ Workshop will be co-located with ICFP 2018.

The workshop does not have proceedings. Talks and/or demos are proposed by submitting an abstract and selected by a small program committee. The workshop will be informal and interactive, with a flexible timetable and plenty of room for ad-hoc discussion, demos, and impromptu short talks.

Invited Speaker

Rahul Muttineni, who brought the joys of Haskell to the realm of Java by creating the Eta programming language, will give the keynote.

Let’s Go Mainstream with Eta!

Abstract: Eta is a fork of GHC that focuses on three core principles: user experience, performance, and safety. We’ll discuss how we used these principles to guide the re-implementation of the GHC runtime and code generator on the JVM. Moreover, will also cover the inner workings of the FFI and the typechecker support we added for subtyping to make it smooth to interact with Java libraries. Finally, we’ll round out with a look at where Eta is headed and how Eta and GHC can collaborate in the future.

Lightning Talks

Like in the previous years, we will have slots for lightning talks. And because they were so successful last year, we will have more!


Anything related to Haskell implementations, fun uses of Haskell etc. goes. Feel free to tell us about ongoing work, to entertain, to rant, to stir a debate!


  • There are 3 sets of 3 lightning talks.
  • Sign-up is on day of the event. No prior registration possible.
    To sign up, send me (@Joachim Breitner) a message on the Strangeloop Slack (https://strangeloop2018.slack.com/). The Channel #icfp-hiw has a pinned message that lists the current schedule.
    If you can’t use Slack, you can talk to me in person.
  • Lightning talks are 8 mins or less.
    If you know that your lightning talk takes less time, please say so, and maybe we can put four lightning talks into the slot.
  • Lightning talks do not count as peer-reviewed publications and are not published in the conference proceedings.
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Sun 23 Sep

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09:00 - 10:00
Invited TalkHIW at Illinois Central
Chair(s): Joachim Breitner DFINITY Foundation
Day opening
Welcome to HIW
Joachim Breitner DFINITY Foundation
Invited Talk: Let’s Go Mainstream with Eta!
Media Attached

Call for Talks

The 10th Haskell Implementors’ Workshop is to be held alongside ICFP 2018 this year in St. Louis. It is a forum for people involved in the design and development of Haskell implementations, tools, libraries, and supporting infrastructure, to share their work and discuss future directions and collaborations with others.

Talks and/or demos are proposed by submitting an abstract, and selected by a small program committee. There will be no published proceedings. The workshop will be informal and interactive, with open spaces in the timetable and room for ad-hoc discussion, demos and lightning talks.

Scope and Target Audience

It is important to distinguish the Haskell Implementors’ Workshop from the Haskell Symposium which is also co-located with ICFP 2018. The Haskell Symposium is for the publication of Haskell-related research. In contrast, the Haskell Implementors’ Workshop will have no proceedings – although we will aim to make talk videos, slides and presented data available with the consent of the speakers.

The Implementors’ Workshop is an ideal place to describe a Haskell extension, describe works-in-progress, demo a new Haskell-related tool, or even propose future lines of Haskell development. Members of the wider Haskell community encouraged to attend the workshop – we need your feedback to keep the Haskell ecosystem thriving. Students working with Haskell are specially encouraged to share their work.

The scope covers any of the following topics. There may be some topics that people feel we’ve missed, so by all means submit a proposal even if it doesn’t fit exactly into one of these buckets:

  • Compilation techniques
  • Language features and extensions
  • Type system implementation
  • Concurrency and parallelism: language design and implementation
  • Performance, optimisation and benchmarking
  • Virtual machines and run-time systems
  • Libraries and tools for development or deployment


We invite proposals from potential speakers for talks and demonstrations. We are aiming for 20-minute talks with 5 minutes for questions and changeovers. We want to hear from people writing compilers, tools, or libraries, people with cool ideas for directions in which we should take the platform, proposals for new features to be implemented, and half-baked crazy ideas. Please submit a talk title and abstract of no more than 300 words.

Submissions can be made via HotCRP at https://icfp-hiw18.hotcrp.com/ until July 20th (anywhere on earth).

We will also have lightning talks session. These have been very well received in recent years, and we aim to increase the time available to them. Lightning talks be ~7mins and are scheduled on the day of the workshop. Suggested topics for lightning talks are to present a single idea, a work-in-progress project, a problem to intrigue and perplex Haskell implementors, or simply to ask for feedback and collaborators.

Program Committee

  • Edwin Brady (University of St. Andrews, UK)
  • Joachim Breitner – chair (University of Pennsylvania)
  • Ben Gamari (Well-Typed LLP)
  • Michael Hanus (Kiel University)
  • Roman Leshchinsky (Facebook)
  • Niki Vazou (University of Maryland)