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 ....
Jan 25, 2026•1 hr 4 min•Season 1Ep. 76
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....
Jan 11, 2026•51 min•Season 1Ep. 75
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 ...
Dec 19, 2025•1 hr 21 min•Season 1Ep. 74
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.
Nov 13, 2025•38 min•Season 1Ep. 73
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.
Oct 30, 2025•57 min•Season 1Ep. 72
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.
Oct 16, 2025•50 min•Season 1Ep. 71
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.....
Sep 14, 2025•1 hr 2 min•Season 1Ep. 70
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.
Aug 25, 2025•53 min
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.
Aug 12, 2025•55 min•Season 1Ep. 68
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.
Jul 07, 2025•57 min•Season 1Ep. 67
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, ...
Jun 24, 2025•1 hr 13 min•Season 1Ep. 66
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.
May 30, 2025•1 hr 1 min•Season 1Ep. 65
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.
Apr 23, 2025•49 min•Ep. 64
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.
Mar 17, 2025•58 min•Ep. 63
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.
Feb 17, 2025•58 min
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.
Jan 22, 2025•58 min•Season 1Ep. 61
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!
Dec 22, 2024•49 min
Sam and Wouter interview Harry Goldstein, a researcher in property-based testing who works in PL, SE, and HCI. In this episode, we reflect on random generators, the find-a-friend model, interdisciplinary research, and how to have impact beyond your own research community.
Dec 11, 2024•43 min•Ep. 59
In this episode, Matti and Sam traveled to the International Conference on Functional Programming (ICFP 2024) in Milan, Italy, and recorded snippets with various participants, including keynote speakers, Haskell legends, and organizers.
Nov 18, 2024•34 min•Season 1Ep. 58
Gabriele Keller, professor at Utrecht University, is interviewed by Andres and Joachim. We follow her journey through the world as well as programming languages, learn why Haskell is the best environment for embedding languages and how the desire to implement parallel programming sparked the development of type families in Haskell and that teaching functional programming works better with graphics.
Nov 03, 2024•54 min•Season 1Ep. 57
Today on the Haskell Interlude, Matti and Sam are joined by Satnam Singh. Satnam has been a lecturer at Glasgow, and Software Engineer at Google, Meta, and now Groq. He talks about convincing people to use Haskell, laying out circuits and why community matters. PS: After the recording, it was important to Satnam to clarify that his advise to “not be afraid to loose your job” was specially meant to encourage to quit jobs that are not good for you, if possible, but he acknowledges that unfortunate...
Oct 01, 2024•43 min•Season 1Ep. 56
In this episode, Niki and Andres talk with Sebastian, one of the main developers of Lean, currently working at the Lean Focused Research Organization. Today we talk about the addictive notion of theorem provers, what is a sweet spot between dependent types and simple programming and how Lean is both a theorem prover and an efficient general purpose programming language.
Aug 16, 2024•54 min•Season 1Ep. 55
In this episode, Wouter and Sam interview Dominic Orchard. Dominic has many roles, including: senior lecturer at the University of Kent, co-director of the Institute of Computing for Climate Science, and bye-fellow of Queen’s College in Cambridge. We will not only discuss his work on Granule - graded monads, coeffects, and linear types - but also his collaboration with actual scientists to improve the languages with which they work.
Aug 04, 2024•49 min•Season 1Ep. 54
In this episode, Garrett Morris talks with Wouter Swierstra and Niki Vazou about his work on Haskell’s type classes, how to fail successfully, and how to construct a set of ponies.
Jul 18, 2024•47 min•Season 1Ep. 53
Andres and Sam interview Pepe Iborra, exploring his journey from academia via banking to now Meta. In this episode, we discuss Pepe’s involvement in the evolution of the Haskell ecosystem, in particular the ongoing journey to improve the developer experience via work on debuggers, build systems and IDEs.
Jul 02, 2024•57 min•Season 1Ep. 52
Victor Miraldo is interviewed by Niki and Joachim and walks us through this career from a student falling in love with List.foldr through a PhD student using agda to verify cryptographic data structures and generic diff and merge algorithms to a professional developer using Haskell in production. He’ll tell us why the Haskell community is too smart, why there should be a safePerformIO, and that he hopes that Software Engineering could be less like alchemy.
Jun 16, 2024•50 min•Season 1Ep. 51
In this episode Tom Sydney is chatting with Matti Paul and Niki Vazou. Tom is the author of many tools, like sydtest, decking, and nix-ci. He tells us about the rules for sustainable Haskell, how Haskell lets one man do the job of 50, and the secret sauce for open source. Tom Sydney is also looking for work these days, so get in touch!
Jun 01, 2024•41 min•Season 1Ep. 50
Wouter and Joachim interview Arseny Seroka, CEO of Serokell. Arseny got into Haskell because of a bet over Pizza, fell for it because it means fewer steps between his soul and his work, and founded Serokell because he could not get a Haskell job. He speaks about the business side of a Haskell company, about the need for more sales and marketing for Haskell itself, and about the Haskell Developer Certification.
May 15, 2024•48 min•Season 1Ep. 49
In this episode, Andres Löh and Matthías Páll Gissurarson interview José Nuno Oliveira, who has been teaching Haskell for 30 years. José talks about how Haskell is the perfect language to introduce programming to all sorts of audiences, why it is important to start with Haskell, and how the programmers of the future have been learning Haskell for several years already!
May 02, 2024•54 min•Season 1Ep. 48
Avi Press is interviewed by Joachim Breitner and Andres Löh. Avi is the founder of Scarf, which uses Haskell to analyze how open source software is used. We’ll hear about the kind of shitstorm telemetry can cause, when correctness matters less than fearless refactoring and how that can lead to statically typed Stockholm syndrome.
Apr 17, 2024•54 min•Season 1Ep. 47
