The Haskell Interlude

Peter is a professor at the University of Freiburg, and he was doing functional programming right when Haskell got started. So naturally we asked him about the early days of Haskell, and how from the start Peter pushed the envelope on what you could do with the type system and specifically with the type classes, from early web programming to program generation to session types. Come with us on a trip down memory lane!

In this episode, we focus on a particular part of Haskell: teaching it. To help us, we are joined by Jamie Willis who is a Teaching Fellow at Imperial College London. The episode explores the benefits of live coding, and why Haskell is the best language for teaching programming.

Franz Thoma is Principal Consultant at TNG Technology Consulting, and an organizer of MuniHac. Franz sees functional programming and Haskell as a tool for thinking about software, even if the project is not written in Haskell. We had a far-reaching conversation about the differences between functional and object-oriented programming and their languages, software architecture, and Haskell adoption in industry.

Welcome to the Haskell Interlude. Today, Matti and Mike talk to Jeffrey Young. Jeff has had a long history of working with Haskell and on ghc itself. We talk about what makes Haskell so compelling, the good and bad of highly optimized code and the beauty of well-modularized code, how to get into compiler development, and how to benefit from Domain-Driven Design. Jeff is currently on the job market - if you want to get in touch, email him at mailto:jmy6342@gmail.com.

We are joined by Kathrin Stark, a professor at Heriot-Watt University in Edinburgh. Kathrin works on program verification with proof assistants, so her focus is not exactly on Haskell, but on topics dear to Haskellers' hearts such as interactive theorem provers, writing correct programs, and the activities needed to produce them. We discuss many aspects of proofs and specifications, and the languages involved in the process, as well as verifying and producing provably correct neural networks.

This episode is a deep dive into the evolution of Haskell and functional programming with one of its pioneers, Lennart Augustson. It reflects on decades of work in language design and compiler implementation. Lennart speaks about his early involvement in the creation of Haskell, shares thoughts on type systems, performance, and the balance between purity and practicality. The conversation ranges from personal history to big-picture views on the evolution of programming languages, with plenty of insight into what makes Haskell both powerful and challenging. A rare opportunity to hear from one of the foundational voices in the functional programming world.

In this Interlude, we’re joined by Jean-Philipe Bernardy, a Senior Lecturer at University of Gothenburg and Chalmers University of Technology. We discuss letting types be your guide, getting into AI to feed yourself, and never testing your programs.

In this episode, we talk to Manuel Chakravarty - specifically, his work on the ghc backend such as data-parallel Haskell and the FFI and how that work segued into type system design. We also discussed Manuel's perspective on Haskell from the language design of Swift.

Stefan Wehr is a professor at the Offenburg University of Applied Sciences. Before becoming a professor, Stefan worked in industry on a large Haskell codebase - specifically one that's not a compiler and not a blockchain. So of course we talked about using Haskell in large projects, software architecture, modularity, type classes and data modeling and the suppression of sums outside of functional programming, and also about teaching Haskell at his current job.

We sat down with Phil Wadler, one of the most influential folks in the Haskell community, functional programming, and programming languages, responsible for type classes, monads, and much more. We take a stroll down memory lane, starting from Haskell's inception. We talked about the difference between research and Phil's work on impactful industrial projects and standards - specifically XML and the design of generics in Java, as well as Phll's teaching at the University of Edinburgh using Agda.. Phil is a fountain of great ideas and stories, and this conversation could have gone on for hours. As it is, we hope you enjoy the hour that we had as much as we did.

Today’s guest is Jurriaan Hage. Jurriaan is a professor at Heriot-Watt University in Edinburgh who’s worked with and on Haskell for many years. He’s known for the Helium Haskell compiler, specifically designed for teaching, and he has plenty of other projects related to Haskell, including improvements to the type system, the generation of better error messages, or detection of plagiarism.

In this episode, we’re joined by Michael Snoyman, author of Yesod, Conduit, Stackage and many other popular Haskell libraries. We discuss newcomer friendliness, being a Rustacean vs a Haskellasaur, how STM is Haskell’s best feature and how laziness can be a vice.

Mike and Andres speak to Alex McLean who created the TidalCycles system for electronic music - implemented in Haskell of course. We talk about how Alex got into Haskell coming from Perl, how types helped him think about the structure of music and patterns, the architecture and evolution of TidalCycles, about art, community and making space for new ideas, and lots of things in between.

Niki and Mike talked to Daniele Micciancio who is a professor at UC San Diego. He's been using Haskell for 20 years, and works in lattice cryptography. We talked to him about how he got into Haskell, using Haskell for teaching theoretical computer science and of course for his research and the role type systems and comonads could play in the design of cryptographic algorithms. Along the way, he gave an accessible introduction to post-quantum cryptography which we really enjoyed. We hope you do, too.

Andy Gordon from Cogna is interviewed by Sam and Matti. We learn about Andy’s influential work including the origins of the bind symbol in haskell, and the introduction of lambdas in Excel. We go onto discuss his current work at Cogna on using AI to allow non-programmers to write apps using natural language. We delve deeper into the ethics of AI and consider the most likely AI apocalypse.

In this episode Mike Sperber and Niki Vazou talk with Sandy Maguire, lead compiler engineer at Manifold Valley. They talk about the benefits of using Haskell of course, about all the books Sandy has written, on effects and the problem with monads, on combinator libraries and programming with laws.

On this episode of the Haskell Interlude, Andres Löh and Mike Sperber are joined by Farhad Mehta, a professor at OST Rapperswil, and one of the organizers of ZuriHac. Fahrad tells us about formal methods, building tunnels, the importance of education, and the complicated relationship between academia and industry.

In this episode Wouter Swiestra and Niki Vazou talk with Conal Elliott. Conal discusses doing things just for the poetry, how most programs miss their purpose, and the simplest way to ask a question. Conal is currently working on a book about his ideas and actively looking for partners.

Sam Lindley is a Reader in Programming Languages Design and Implementation at the University of Edinburgh. In this episode, he tells us how difficult naming is, the different kinds of effect systems and handlers, languages *much* purer than Haskell, and Modal logic.

Tom Ellis works at Groq, using Haskell to compile AI models to specialized hardware. In this episode, we talk about stability of both GHC and Haskell libraries, effects, and strictness, and the premise of functional programming: make invalid states and invalid *laziness* unrepresentable!