Andres Löh
@kosmikus.bsky.social
Partner and Haskell Consultant at Well-Typed LLP. Board member of the Haskell Foundation. Co-host of the Haskell Interlude and the Haskell Unfolder.
Posts mostly about Haskell, and occasionally about books, video games, and other things that interest me.
Posts mostly about Haskell, and occasionally about books, video games, and other things that interest me.
There's going to be a new episode of the #Haskell #Unfolder today, 2025-11-12, at 1930 UTC. We're going to discuss how to implement (more) type-safe APIs via some type-level programming using the sop-core package.
www.youtube.com/watch?v=3XeI...
www.youtube.com/watch?v=3XeI...
Typed servers using sop-core (Haskell Unfolder #51)
YouTube video by Well-Typed
www.youtube.com
November 12, 2025 at 1:50 PM
There's going to be a new episode of the #Haskell #Unfolder today, 2025-11-12, at 1930 UTC. We're going to discuss how to implement (more) type-safe APIs via some type-level programming using the sop-core package.
www.youtube.com/watch?v=3XeI...
www.youtube.com/watch?v=3XeI...
Join us tonight for the 50th (!) episode of the #Haskell #Unfolder, on singletons! Live on YouTube 1930 UTC (note the changed time in some countries due to DST-related fluctuations).
www.youtube.com/watch?v=-zxx...
www.youtube.com/watch?v=-zxx...
Singletons (Haskell Unfolder #50)
YouTube video by Well-Typed
www.youtube.com
October 29, 2025 at 12:26 PM
Join us tonight for the 50th (!) episode of the #Haskell #Unfolder, on singletons! Live on YouTube 1930 UTC (note the changed time in some countries due to DST-related fluctuations).
www.youtube.com/watch?v=-zxx...
www.youtube.com/watch?v=-zxx...
Join us today, 2025-10-15, at 1830 UTC, for a new episode of the #Haskell #Unfolder, on the importance of shrinking for property-based testing: www.youtube.com/watch?v=EcV4...
Shrinking (Haskell Unfolder #49)
YouTube video by Well-Typed
www.youtube.com
October 15, 2025 at 1:55 PM
Join us today, 2025-10-15, at 1830 UTC, for a new episode of the #Haskell #Unfolder, on the importance of shrinking for property-based testing: www.youtube.com/watch?v=EcV4...
After a long summer break, we're finally back for a new episode of the #Haskell #Unfolder: Edsko and I are going to talk about safe coercions, newtype vs data, roles and more ... Today, 2025-10-01, 1830 UTC on YouTube: www.youtube.com/watch?v=NC0w...
Safe coercions (Haskell Unfolder #48)
YouTube video by Well-Typed
www.youtube.com
October 1, 2025 at 8:48 AM
After a long summer break, we're finally back for a new episode of the #Haskell #Unfolder: Edsko and I are going to talk about safe coercions, newtype vs data, roles and more ... Today, 2025-10-01, 1830 UTC on YouTube: www.youtube.com/watch?v=NC0w...
Reposted by Andres Löh
We have confirmed three keynotes for MuniHac 2025. Join us in Munich between September 12th and 14th for talks by Andrew Lelechenko, @sperbsen.bsky.social, and Rodrigo Mesquita as well as workshops and hacking projects: munihac.de/2025.html#re...
#MuniHac #Haskell
#MuniHac #Haskell
August 4, 2025 at 10:02 AM
We have confirmed three keynotes for MuniHac 2025. Join us in Munich between September 12th and 14th for talks by Andrew Lelechenko, @sperbsen.bsky.social, and Rodrigo Mesquita as well as workshops and hacking projects: munihac.de/2025.html#re...
#MuniHac #Haskell
#MuniHac #Haskell
Join us today, 2025-07-23, 1830 UTC, live on YouTube for a new episode of the #Haskell #Unfolder, this time on "pure parallelism".
www.youtube.com/watch?v=trDq...
www.youtube.com/watch?v=trDq...
Pure parallelism (Haskell Unfolder #47)
YouTube video by Well-Typed
www.youtube.com
July 23, 2025 at 3:18 PM
Join us today, 2025-07-23, 1830 UTC, live on YouTube for a new episode of the #Haskell #Unfolder, this time on "pure parallelism".
www.youtube.com/watch?v=trDq...
www.youtube.com/watch?v=trDq...
Today, Wednesday, 2025-07-09, at 1830 UTC, there's going to be a new episode of the #Haskell #Unfolder. Edsko and I will show how to develop a small but useful Haskell CLI application completely from scratch.
www.youtube.com/watch?v=5W0Z...
www.youtube.com/watch?v=5W0Z...
Developing an application from scratch (Haskell Unfolder #46)
YouTube video by Well-Typed
www.youtube.com
July 9, 2025 at 8:23 AM
Today, Wednesday, 2025-07-09, at 1830 UTC, there's going to be a new episode of the #Haskell #Unfolder. Edsko and I will show how to develop a small but useful Haskell CLI application completely from scratch.
www.youtube.com/watch?v=5W0Z...
www.youtube.com/watch?v=5W0Z...
Reposted by Andres Löh
Better infrastructure, fewer surprises. We’re raising $6K for a dedicated ARM server to support #Haskell’s infrastructure (CI, backups, etc). Let’s build infra you can rely on! Every contribution helps!
Donate: donorbox.org/infrastructu...
Read more: discourse.haskell.org/t/infrastruc...
Donate: donorbox.org/infrastructu...
Read more: discourse.haskell.org/t/infrastruc...
Infrastructure Independence | Haskell.org, Inc (Powered by Donorbox)
Historically, the Haskell community has relied on a mix of cloud providers and self-hosted servers for our core infrastructure (Hackage, Stackage, GHC, CI, etc.). More recently the Haskell Infrastruct...
donorbox.org
July 7, 2025 at 3:11 PM
Better infrastructure, fewer surprises. We’re raising $6K for a dedicated ARM server to support #Haskell’s infrastructure (CI, backups, etc). Let’s build infra you can rely on! Every contribution helps!
Donate: donorbox.org/infrastructu...
Read more: discourse.haskell.org/t/infrastruc...
Donate: donorbox.org/infrastructu...
Read more: discourse.haskell.org/t/infrastruc...
Reposted by Andres Löh
Well, unless we do something about it.
This battle will keep playing out over and over again until they achieve something that their own citizens have made it clear they don’t want. www.techradar.com/vpn/vpn-priv...
The EU wants to decrypt your private data by 2030
The EU Commission unveiled the first step in its security strategy to ensure "lawful and effective" law enforcement access to data
www.techradar.com
July 6, 2025 at 10:57 AM
Well, unless we do something about it.
On Wednesday, 2025-06-25, at 1830 UTC, there will be a new episode of the #Haskell #Unfolder. This time, Edsko and I will discuss the current situation of records in Haskell.
www.youtube.com/watch?v=9hrD...
www.youtube.com/watch?v=9hrD...
Haskell records in 2025 (Haskell Unfolder #45)
YouTube video by Well-Typed
www.youtube.com
June 24, 2025 at 2:12 PM
On Wednesday, 2025-06-25, at 1830 UTC, there will be a new episode of the #Haskell #Unfolder. This time, Edsko and I will discuss the current situation of records in Haskell.
www.youtube.com/watch?v=9hrD...
www.youtube.com/watch?v=9hrD...
If you want to hear from Edsko and me how to test stateful APIs using quickcheck(-lockstep), join us today, 2025-05-14, at 1830 UTC, live on YouTube for a new episode of the #Haskell #Unfolder: www.youtube.com/watch?v=RPQV...
State-based testing with quickcheck-lockstep (Haskell Unfolder #44)
YouTube video by Well-Typed
www.youtube.com
May 14, 2025 at 3:00 PM
If you want to hear from Edsko and me how to test stateful APIs using quickcheck(-lockstep), join us today, 2025-05-14, at 1830 UTC, live on YouTube for a new episode of the #Haskell #Unfolder: www.youtube.com/watch?v=RPQV...
Today, there will be a new #Haskell #Unfolder episode, where Edsko and I will talk about the monomorphism restriction and defaulting. Join us live on YouTube 2025-05-07 at 1830 UTC (or watch later) via www.youtube.com/watch?v=nD93...
The Haskell Unfolder Episode 43: monomorphism restriction and defaulting
YouTube video by Well-Typed
www.youtube.com
May 7, 2025 at 1:16 PM
Today, there will be a new #Haskell #Unfolder episode, where Edsko and I will talk about the monomorphism restriction and defaulting. Join us live on YouTube 2025-05-07 at 1830 UTC (or watch later) via www.youtube.com/watch?v=nD93...
Reposted by Andres Löh
The video of @kosmikus.bsky.social's #BOBkon2025 talk "Abstraction and program design, or the power of parametricity" is now up!
bobkonf.de/2025/loeh.html
bobkonf.de/2025/loeh.html
May 7, 2025 at 1:03 PM
The video of @kosmikus.bsky.social's #BOBkon2025 talk "Abstraction and program design, or the power of parametricity" is now up!
bobkonf.de/2025/loeh.html
bobkonf.de/2025/loeh.html
The #Haskell #Unfolder is two years old! Join us for a new episode tomorrow, 2025-04-16, at 1830 UTC, live on YouTube. This time, the topic is logic programming with typedKanren, which is a typed version of #miniKanren embedded into Haskell.
www.youtube.com/watch?v=ukk5...
www.youtube.com/watch?v=ukk5...
The Haskell Unfolder Episode 42: logic programming with typedKanren
YouTube video by Well-Typed
www.youtube.com
April 15, 2025 at 2:49 PM
The #Haskell #Unfolder is two years old! Join us for a new episode tomorrow, 2025-04-16, at 1830 UTC, live on YouTube. This time, the topic is logic programming with typedKanren, which is a typed version of #miniKanren embedded into Haskell.
www.youtube.com/watch?v=ukk5...
www.youtube.com/watch?v=ukk5...
Reposted by Andres Löh
I'm thinking about a second edition of Parallel and Concurrent Programming in Haskell. Any thoughts on what should be added (or removed)? What's missing, what updates are needed to reflect common usage?
The obvious new things are async and Haxl. Should the chapter on distributed-process be kept?
The obvious new things are async and Haxl. Should the chapter on distributed-process be kept?
March 28, 2025 at 3:01 PM
I'm thinking about a second edition of Parallel and Concurrent Programming in Haskell. Any thoughts on what should be added (or removed)? What's missing, what updates are needed to reflect common usage?
The obvious new things are async and Haxl. Should the chapter on distributed-process be kept?
The obvious new things are async and Haxl. Should the chapter on distributed-process be kept?
Tonight, 2025-03-26, at 1930 UTC (still an unusual time for US/Canada) there'll be a new episode of the #Haskell #Unfolder, and after all this time, we'll finally talk about generics!
www.youtube.com/watch?v=db-K...
www.youtube.com/watch?v=db-K...
The Haskell Unfolder Episode 41: generic monoids
YouTube video by Well-Typed
www.youtube.com
March 26, 2025 at 3:14 PM
Tonight, 2025-03-26, at 1930 UTC (still an unusual time for US/Canada) there'll be a new episode of the #Haskell #Unfolder, and after all this time, we'll finally talk about generics!
www.youtube.com/watch?v=db-K...
www.youtube.com/watch?v=db-K...
Reposted by Andres Löh
Please consider submitting to FUNARCH 2025, a workshop that is part of the @icfp-conference.bsky.social week in Singapore this October. At the intersection of software engineering and functional programming, bsky.app/profile/funa...
conf.researchr.org/home/icfp-sp...
conf.researchr.org/home/icfp-sp...
FUNARCH 2025 - ICFP/SPLASH 2025
The Third ACM SIGPLAN Workshop on Functional Software Architecture - FP in the Large
“Functional Software Architecture” refers to methods of construction and structure of large and long-lived softwar...
conf.researchr.org
March 21, 2025 at 6:53 PM
Please consider submitting to FUNARCH 2025, a workshop that is part of the @icfp-conference.bsky.social week in Singapore this October. At the intersection of software engineering and functional programming, bsky.app/profile/funa...
conf.researchr.org/home/icfp-sp...
conf.researchr.org/home/icfp-sp...
Reposted by Andres Löh
Unser C*O @sperbsen.bsky.social und @kosmikus.bsky.social haben gemeinsam die neuste Folge des Podcasts der Haskell Foundation (Haskell Interlude) moderiert: ein Gespräch mit Farhad Mehta, Professor für Informatik (OST Rapperswil) & @zurihac.bsky.social-Organisator.
haskell.foundation/podcast/63/
haskell.foundation/podcast/63/
March 18, 2025 at 12:59 PM
Unser C*O @sperbsen.bsky.social und @kosmikus.bsky.social haben gemeinsam die neuste Folge des Podcasts der Haskell Foundation (Haskell Interlude) moderiert: ein Gespräch mit Farhad Mehta, Professor für Informatik (OST Rapperswil) & @zurihac.bsky.social-Organisator.
haskell.foundation/podcast/63/
haskell.foundation/podcast/63/
Tomorrow, 2025-03-12, at 1930 UTC (note: one hour later than usual in Canada / US due to asynchronous DST shifts), there'll be a new episode of the #Haskell #Unfolder, titled "understanding through a model". We'll talk about QuickCheck and convolutions ...
www.youtube.com/watch?v=0QTt...
www.youtube.com/watch?v=0QTt...
The Haskell Unfolder Episode 40: understanding through a model
YouTube video by Well-Typed
www.youtube.com
March 11, 2025 at 7:10 PM
Tomorrow, 2025-03-12, at 1930 UTC (note: one hour later than usual in Canada / US due to asynchronous DST shifts), there'll be a new episode of the #Haskell #Unfolder, titled "understanding through a model". We'll talk about QuickCheck and convolutions ...
www.youtube.com/watch?v=0QTt...
www.youtube.com/watch?v=0QTt...
Reposted by Andres Löh
#BOBkonf2025 is two weeks away, and we only have very few tickets left -- the location will let us bump the numbers until Monday, so get your ticket now if you haven't already!
bobkonf.de/2025/registr...
bobkonf.de/2025/registr...
February 28, 2025 at 8:01 AM
#BOBkonf2025 is two weeks away, and we only have very few tickets left -- the location will let us bump the numbers until Monday, so get your ticket now if you haven't already!
bobkonf.de/2025/registr...
bobkonf.de/2025/registr...
Please consider nominating yourself to be a member of the Board of the #Haskell Foundation: discourse.haskell.org/t/2025-call-...
2025 Call for nominations for the Haskell Foundation
Hello! everyone The Haskell Foundation’s directors are pleased to announce the nomination process for seats on the Foundation’s board of directors. The board is the ultimate decision-making body of ...
discourse.haskell.org
February 25, 2025 at 5:10 PM
Please consider nominating yourself to be a member of the Board of the #Haskell Foundation: discourse.haskell.org/t/2025-call-...
Tomorrow, 2025-02-11, we'll live-stream a new episode of the #Haskell #Unfolder. Edsko and I will discuss the various strategies for deriving instances that GHC offers and their relative strengths and weaknesses. Hope to see you all there! www.youtube.com/watch?v=NEUb...
The Haskell Unfolder Episode 39: deriving strategies
YouTube video by Well-Typed
www.youtube.com
February 11, 2025 at 8:41 PM
Tomorrow, 2025-02-11, we'll live-stream a new episode of the #Haskell #Unfolder. Edsko and I will discuss the various strategies for deriving instances that GHC offers and their relative strengths and weaknesses. Hope to see you all there! www.youtube.com/watch?v=NEUb...
Reposted by Andres Löh
@kosmikus.bsky.social will be at #BOBkonf2025 with "Abstraction and program design, or the power of parametricity":
bobkonf.de/2025/loeh.html
bobkonf.de/2025/loeh.html
January 22, 2025 at 2:24 PM
@kosmikus.bsky.social will be at #BOBkonf2025 with "Abstraction and program design, or the power of parametricity":
bobkonf.de/2025/loeh.html
bobkonf.de/2025/loeh.html
The #Haskell #Unfolder is back! In tomorrow's episode, we'll take a look at #CUDA and write some simple functions in it. We'll also show how to interface from Haskell to CUDA and how to use QuickCheck to test CUDA functions from Haskell.
www.youtube.com/watch?v=ww4C...
www.youtube.com/watch?v=ww4C...
The Haskell Unfolder Episode 38: tasting and testing CUDA (map, fold, scan)
YouTube video by Well-Typed
www.youtube.com
January 14, 2025 at 4:02 PM
The #Haskell #Unfolder is back! In tomorrow's episode, we'll take a look at #CUDA and write some simple functions in it. We'll also show how to interface from Haskell to CUDA and how to use QuickCheck to test CUDA functions from Haskell.
www.youtube.com/watch?v=ww4C...
www.youtube.com/watch?v=ww4C...
Tomorrow, 2024-12-04, at 1930 UTC, there'll be a new episode of the #Haskell #Unfolder live on YouTube. This time, we'll try to solve Day 4 of #AdventOfCode 2024.
www.youtube.com/watch?v=KkKx...
www.youtube.com/watch?v=KkKx...
The Haskell Unfolder Episode 37: solving Advent of Code 2024 day 4
YouTube video by Well-Typed
www.youtube.com
December 3, 2024 at 7:56 PM
Tomorrow, 2024-12-04, at 1930 UTC, there'll be a new episode of the #Haskell #Unfolder live on YouTube. This time, we'll try to solve Day 4 of #AdventOfCode 2024.
www.youtube.com/watch?v=KkKx...
www.youtube.com/watch?v=KkKx...