THE VIDEO SHELF · type classes
Edward Kmett - Type Classes vs. the World
Edward Kmett speaks at the Boston Haskell meetup about type classes and the design tradeoffs of global coherence compared with other approaches to implicit instances. It covers why uniqueness of instances matters for reasoning and refactoring.
Why HN readers recommended it
HN points to it as the definitive explanation of why coherence and the orphan rule matter, in debates over Haskell, Rust traits, OCaml modules and Elm.
This is a summary from the source dataset, not an endorsement by Hacker News or the video creator.
Video & recommendation details
- Creator / channel
- Boston Haskell
- Topic
- type classes
- Format
- talk
- Level
- advanced
- HN recommenders in dataset
- 2
- HN mentions in dataset
- 6
- Recommendation years in dataset
- 2015–2024
These counts and years describe the included Hacker News records; they are not YouTube views or the video’s publication date.
From the original HN conversations
Excerpts from the recorded comments. Follow each source for the full comment and surrounding discussion.
The point is a little more subtle than this, or how the article made it out to be. Global coherence and confluence (which GHC attempts to enforce unless told otherwise) is great for refactoring and equational reasoning and (yes) mathematics and programming at large, as …
shadytrees on Hacker News · 2015-09
In Haskell's Type Classes: We Can Do BetterEdward Kmett has a great explanation[1] of the considerations around this space. It's not that alternatives to the orphan rule are hard to implement, it's that they lead to things being much harder to reason about for the programmer. [1]: [VIDEO]
Twey on Hacker News · 2023-08
In This isn’t the way to speed up Rust compile times
Summaries, classifications and recommendation records are from the HackerTube source dataset. Read about this library and its limitations.