# What Color is Your Function? by Bob Nystrom

5 Hacker News commenters recommended What Color is Your Function? by Bob Nystrom and 0 criticized it, November 2025 to November 2026. It was recommended in 3 of 13 months.

**Verdict:** Recommended as a clear, widely praised explanation of function colors and async; critics say it covers only part of concurrency and offers little deep insight.

## Why people recommend it

- Makes the function color problem easy to grasp (1 comments): "it makes a certain ick very easy to feel and understand, but it doesn't offer much in terms of profound knowledge" ([source](https://news.ycombinator.com/item?id=48286068))
- Praised as a wonderful article (1 comments): "the (wonderful!) function color article" ([source](https://news.ycombinator.com/item?id=46739049))

## What people warn about

- Covers only part of concurrency (1 comments): "they tend to pick on a a subset of the properties that make up this complex topic of concurrency" ([source](https://news.ycombinator.com/item?id=45788269))
- Shallow on profound knowledge (1 comments): "it makes a certain ick very easy to feel and understand, but it doesn't offer much in terms of profound knowledge" ([source](https://news.ycombinator.com/item?id=48286068))
- Heavy chained closures at runtime (1 comments): "his main criticism here is the big mess of chained closures this makes at runtime, compared with pausing/resuming green threads" ([source](https://news.ycombinator.com/item?id=48287138))

## Alternatives hackers recommend

- [Programming as Theory Building by Peter Naur](https://hackerapproved.com/p/programming-as-theory-building.md): 32 recommend
- [Ur-Fascism by Umberto Eco](https://hackerapproved.com/p/ur-fascism.md): 18 recommend
- [Politics and the English Language by George Orwell](https://hackerapproved.com/p/politics-and-the-english-language.md): 14 recommend
- [Right to Read by Richard Stallman](https://hackerapproved.com/p/right-to-read.md): 12 recommend
- [Meditations on Moloch by Scott Alexander](https://hackerapproved.com/p/meditations-on-moloch.md): 11 recommend

## Cite as

Hacker Approved, "What Color is Your Function? by Bob Nystrom", https://hackerapproved.com/p/what-color-is-your-function/ (counts from 1,795,640 Hacker News comments, November 2025 to November 2026).