Today, 2025-04-16, at 1830 UTC (11:30 am PDT, 2:30 pm EDT, 7:30 pm GMT, 20:30 CET, …) we are streaming the 42th episode of the Haskell Unfolder live on YouTube.

The Haskell Unfolder Episode 42: logic programming with typedKanren

Functional programming is programming with mathematical functions, mapping inputs to outputs. By contrast, logic programming—perhaps best known from the language Prolog—is programming with mathematical relations between values, without making a distinction between inputs and outputs. In this two-year anniversary episode of the Haskell Unfolder we take a look at typedKanren, an embedding of the logic programming language miniKanren in Haskell. We will see how we can use it to write a type checker for a simple functional language in a few lines of code.

About the Haskell Unfolder

The Haskell Unfolder is a YouTube series about all things Haskell hosted by Edsko de Vries and Andres Löh, with episodes appearing approximately every two weeks. All episodes are live-streamed, and we try to respond to audience questions. All episodes are also available as recordings afterwards.

We have a GitHub repository with code samples from the episodes.

And we have a public Google calendar (also available as ICal) listing the planned schedule.

There’s now also a web shop where you can buy t-shirts and mugs (and potentially in the future other items) with the Haskell Unfolder logo.