- Author
- Posted by zeepthee, with replies from many commenters
- Published
- 12 September 2025
- Kind
- Hacker News discussion thread
- Original
- news.ycombinator.com/item?id=45221112
- Subject
- Programming languages and types
What it is
Zeepthee posted the link to Hacker News and many users replied. The linked post is titled Death to type classes. The thread is mostly reaction to its audience and its ideas.
What it says
- Several commenters say the post assumes knowledge of OCaml, Haskell and Backpack.
- Commenter fweimer says the post uses the Backpack extension, not the basic Haskell module system.
- Commenter wk_end explains that ML functors take modules as arguments, which overlaps with type classes.
- Commenter wavemode says type classes act like an extra vtable argument.
- Commenter acomar says Backpack is powerful in theory but almost unused in real code.
- Commenter wavemode recalls many Haskell attempts at better effects, from mtl to free monads.
- Commenter marcosdumay sees no gain over type classes. Yuppiemephisto calls the post a nice tutorial.
What evidence it gives
The thread offers opinion, explanation and links from commenters. It has no benchmarks or tests.
Interests and limits
The linked post was not fetched. Its argument is described only through commenters. Many replies say they could not follow it. Claims about Backpack and Haskell come from anonymous replies and were not checked.