hackertube.io

Lenses, Folds, and Traversals

Edward Kmett · talk · Watch on YouTube

Functional programmingProgramming language design

What it is

Edward Kmett's talk to the NY Haskell User Group on the lens library, building from fmap and function composition up to lenses, folds and traversals. It shows how these composable combinators access and modify parts of data structures.

Why Hacker News recommends it

HN calls it dense but mind-blowing, the go-to way to understand lenses through algebraic derivation.

  • 3 people recommended it
  • 3 different months
  • 1 strong recommendations
  • first 2013, last 2014

What HN commenters said

  1. “I found this talk by edward kmett incredibly helpful[0].”

    Dense but mind-blowing introduction to lenses and traversals

    mijoharas, 2014-11 · Strong recommendation · in “How I Start: Haskell”

  2. “Edward Kmett's video on his lens library walks through how you can derive it with this sort of logic”

    Kmett derives the lens library through algebraic reasoning

    jerf, 2013-01 · Recommendation · in “Why is the C++ STL so heavily based on templates?”

  3. “Great things the parent has done with the language”

    Showcase of great things done in Haskell

    dllthomas, 2014-08 · Recommendation · in “Letter to a Young Haskell Enthusiast”

Excerpts from Hacker News comments, linked to the originals. Summaries and labels were written by a language model from those comments.

Topics: haskell, lens, traversals, functional programming, category theory

Also recommended by the same people