Category Theory for Programmers

The cluster focuses on Hacker News users questioning the popularity of category theory, seeking explanations of its relevance to programming (especially functional languages like Haskell), and requesting beginner-friendly resources such as 'Category Theory for Programmers'.

📉 Falling 0.2x Programming Languages
3,155
Comments
18
Years Active
5
Top Authors
#7074
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Keywords

e.g JS HN bartoszmilewski.com IS and.html wordpress.com CT sigfpe.com wikipedia.org category theory category theory haskell mathematics concepts programming objects categories mathematicians

Sample Comments

Pardon me: what IS category theory?

syats Jan 3, 2017 View on HN

If I may ask, why is the HN community so interested in this particular topic? I studied Math and have basic understanding of Category Theory... could someone point me to a text relating Categories and... something related to computers? What am I missing?

Schiphol Nov 11, 2015 View on HN

Is there a 'category theory for programmers' text anyone could recommend?

ZephyrP Nov 17, 2011 View on HN

No mention of Category Theory.:(

Koshkin May 3, 2020 View on HN

My view on this is that Category Theory is more of a framework for your brain rather than for your computer. As the founders of the theory had noted, categories were introduced as a basis for explaining what a functor is, and functors were needed to explain the phenomenon of natural equivalence. It is indeed practically useful to program your brain in such a way that you could better discern common patterns and be able to see that what you are trying to do is equivalent to somethin

hamburgererror Oct 1, 2025 View on HN

What's the thing with category theory? I see this topic discussed quite frequently here but I don't get it why people are so into it

xyzzyz Jun 30, 2011 View on HN

What's the deal with category theory on HN? Seriously, how is it interesting or relevant without introducing it along with concepts from fields in which it is of main use (e.g. (homological) algebra and algebraic toplogy)? I don't think I'd be able to appreciate, or even understand CT without having a thorough understanding of concepts it tries to generalize -- hell, I do have trouble to consider it useful even with it. Since I do not believe that HN us full of mathematicians (even though there

umanwizard Feb 10, 2019 View on HN

Why do you want to learn category theory?

jules Apr 1, 2008 View on HN

Why should someone who is interested in programming languages learn category theory and what is the best (preferably online) text?

throwawaymath Feb 10, 2019 View on HN

Very well said. The practical reality is that the “category theory” used in functional programming paradigms (like Haskell’s) has only a passing resemblence to formal category theory in mathematics. It’s a nice idea to formalize some concepts in functional programming algebraically, but learning formal category theory won’t realistically improve your programming ability. There is some conceptual overlap, but they’re just very different things.