Lightning Talk: Making and Testing Code Generators in Haskell

Featuring Michał Gajda

Michał and the Migamake Pte Ltd team are currently making an open source library to help produce code generators in Haskell. It facilitates generating code with syntax-checked templates and unit testing with smaller and more robust tests Michał will go through code generation approaches seen in...

haskell generators

GHC Runtime Linker by Example

Featuring Artem Pyanykh

Linkers are one of the least understood yet widely used software components. GHC, unlike many other projects, has its own rather complex linking facilities in the runtime system that among other things power our beloved GHCi. And while having a custom linker has its benefits there are also...

haskell runtime linker compiler ghc

Higher-Order Type-Level Programming

Featuring Csongor Kiss

Thanks to its myriad of extensions, GHC's type system has come a long way in offering a powerful language for expressing complex programs at the type-level.

type-level-programming haskell ghc types

Stick to Simple Haskell

Featuring Marco Sampellegrini

Three years ago Marco set out to learn Haskell. He eventually joined a company to work with Haskell full time. That was it: no more runtime errors, no more wasting hours on stupid bugs. Finally living the dream. Except it didn't exactly go down like that.

haskell types type-level ghc

What To Do When You Have Plenty of (Non-)Haskell

Featuring Mathieu Boespflug

Codebases are hard to build. Someone somewhere invariably wants to write custom code preprocessors and generators. Teams each use their own mix of languages (Haskell, C/C++, Rust, Java{Script}, Python...). Changing code induces a lot of rebuilding and GHC requires so much CPU power that it would...

bazel build-systems haskell ghc codebases

Functional Lenses Through a Practical Lens

Featuring Sara Fransson

In the greater Haskell ecosystem, as well as in various industry codebases, libraries sometimes provide lens based APIs. One of the great promises of lenses is to make it easy and smooth to work with Haskell's immutable data structures.

optics lenses haskell

This Ain't Your Daddy's Probability Monad - Modelling Probabilistic Time in Haskell

Featuring Lars Brünjes

It is well known that (discrete) probability distributions can be implemented as monads in Haskell in various more or less sophisticated ways.

haskell network-modelling time probability monad

Build Systems à la Carte

Featuring Andrey Mokhov

Build systems are used by every developer around the world but are rarely the object of study.

shake bazel dune nix haskell build-systems

2

Park Bench Panel

Featuring Abby Sassel and Ben Clifford

monads types ghc haskell

A Type-ical Case Study: The Sound Type-Indexed Type Checker

Featuring Richard Eisenberg

This talk will be an exploration of an implementation of a simply-typed λ-calculus using lots of Haskell's fancy types: only well-typed terms can be represented.

haskell well-typed types

The Scope of Algebraic Effects

Featuring Nicolas Wu

Effect handlers are a clean way of describing various effects in a principled and modular way. The approach models the syntax and semantic of operations, where syntax is given by a free monad, and the semantics is given by a handler. Traditionally, the operations must be algebraic in that they...

haskell effect-handlers free-monad

Keynote: (Programming Languages) in Agda = Programming (Languages in Agda)

Featuring Philip Wadler

The most profound connection between logic and computation is a pun.

functional-programming types propositions agda haskell

Categories and State Machines

Featuring Marcin Szamotulski

Marcin will give a short introduction to categories in Haskell, and he will present free construction of categories which embrace monadic actions and their usefulness to build state machines in Haskell.

haskell state-machines kleisli-categories categories

Using Haskell and Symbolic Execution to Verify Spacecraft Control Programs

Featuring Georgy Lukyanov

Verification of correctness of control programs is an essential task in the development of space electronics; it is difficult and typically outweighs design and programming tasks in terms of development hours

haskell automated-theorem-proving symbolic-execution formal-verification

Keynote: Revisiting Pattern Match Overlap Checks

Featuring Simon Peyton Jones

How hard can it be to spot missing or overlapping patterns in a Haskell function definition? Surely it’s the least we can expect from a decent compiler? But when you mix in GADTs, pattern guards, view patterns, data families, strict data constructors, and pattern synonyms, matters get...

pattern-matching refactored-implementation gadt ghc haskell

Porcupine: Flows Your Rows with Arrows

Featuring Yves Parès

This talk aims at presenting the porcupine (https://github.com/tweag/porcupine) Haskell library and more generally the advantages of using a more constrained framework (in this case, arrow-based) than pure functions and monads to represent parameterizable data pipelines in Haskell.

haskell constrained-framework data porcupine

Automating Elaborate-Transform-Load for Busy Data Scientists

Featuring Michał Gajda

Haskell is making great strides into processing data at greater convenience. You do not only have fast parsers for most important languages, but now automatic parser generators that discover the structure of our documents and package them as Haskell types: DataFrames, JSON Autotype, XML TypeLift....

data haskell parsing csv etl metadata ingest xml json bigdata analytics datascience

Cleaning the Big Picture: Creating Maintainable Mobile Games in Haskell

Featuring Christina Zeller

As game-app developers, you want to create many games that are easy to maintain.

haskell clean-code ios android mobile game-apps

Parsley: A Staged Selective Parser Combinator Library

Featuring Jamie Willis

Parser combinator libraries are a popular approach to writing parsers in the functional world. In particular, monadic parser combinators take centre stage. But when looking to design a performant library, monads provide a hard stopper on potential introspective optimisation opportunities....

haskell domain-specific-languages performance meta-programming parser-combinators parsers

Fixing Haskell Records

Featuring Neil Mitchell

Sadly, Haskell records aren’t very good - problems include that field names must be unique and that record updates are not very expressive. A variety of solutions have been proposed over many decades, but none has gained traction. The closest answer Haskell has is the lens library, which famously...

records haskell daml