The Haskell Unfolder Episode 8: laws

Today, 2023-07-26, at 1000 UTC (that’s less than 30 minutes from the time of this announcement!) we are streaming the 8th episode of the Haskell Unfolder live on YouTube:

Many of Haskell’s abstractions come with laws; well-known examples include the Functor type class with the functor laws and the Monad type class with the monad laws, but this is not limited to type classes; for example, lenses come with a set of laws, too. To people without a mathematical background such laws may seem intimidating; how would one even start to think about proving them for our own abstractions? In this episode of The Haskell Unfolder we will discuss examples of these laws, show how to prove them, and discuss common techniques for such proofs, including induction. We will also discuss why these laws matter; what goes wrong when they do not hold?

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.

We also have a GitHub repository with the code samples from the episodes:

And we have a public Google calendar listing the planned schedule:

(or ICal: )