cross-posted from: https://sopuli.xyz/post/10354955

If "category" has a better name....

Isn't it just "composite"?

Every arrow in category can be composed, the set(or class or whatnot..) of that is composite.

The next #FPIndia Learn #Haskell meetup is going to be this Saturday 24 Feb in #Gurgaon.

We'll do a quick recap of basics of Haskell, and then learn some tricks on how to write real world code. This is a great time to jump in if you have not attended the previous sessions.

Do drop by if you are around!

#FunctionalProgramming #Meetup #Delhi #India

Basic optics: lenses, prisms, and traversals in Haskell

Lenses are becoming an increasingly important part of a Haskeller’s toolkit. Yet, when first approaching them, people may feel buried under a myriad of different lens-like thingies, and the complexity of some of the libraries implementing those concepts, like lens.

The goal of this talk is to provide a conceptual overview of three of the most important kinds of optics, namely lenses, prisms, and traversals. For most data types, those optics can be automatically generated, something we shall discuss. Finally, we shall look at one useful application of optics: treating semi-structured data such as JSON documents.

Joachim Breitner and David Christiansen interview John MacFarlane, a professor of philosophy at UC Berkeley, but also the author of the popular pandoc document conversion tool, which has been around half as long as Haskell itself. He also explains the principle of uniformity as a design goal for lightweight markup languages, the relationship between philosophy and programming, and along the way he helps David with his markdown difficulties.