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milewski-ctfp-pdf
TeX2017–2026
hmemcpy / milewski-ctfp-pdf

milewski-ctfp-pdf

Bartosz Milewski's 'Category Theory for Programmers' unofficial PDF and LaTeX source

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REPOSITORY AT A GLANCE

What to know before exploring

What it is

Bartosz Milewski's 'Category Theory for Programmers' unofficial PDF and LaTeX source

GitHub

Where it is used

No documented product use was verified in the last source check.

What people are saying

This is such a great page, i love it and came across it multiple times while studying the matter. I still would vote to learn it from Milewski though. Learning this is a…

Krei-se used a recommendation phrase. One indexed comment matches. This is a phrase match, not a verdict.

No classified warning is attached to this page. Read the discussions before treating silence as approval.

Also in these discussions

No other repository is repeatedly linked in the same discussions.

This week on Hacker News

Nov 8–Nov 15 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/15/2026, 10:01:16 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by year40 dated mentions

Observed mentions: 2017-09-30 13:53:10 UTC to 2026-07-14 20:08:44 UTC.

02468102017-01-01 00:00:00 UTC to 2018-01-01 00:00:00 UTC (exclusive): 2 mentions; 1 submissions, 1 comments20172018-01-01 00:00:00 UTC to 2019-01-01 00:00:00 UTC (exclusive): 10 mentions; 2 submissions, 8 comments2019-01-01 00:00:00 UTC to 2020-01-01 00:00:00 UTC (exclusive): 9 mentions; 3 submissions, 6 comments2020-01-01 00:00:00 UTC to 2021-01-01 00:00:00 UTC (exclusive): 4 mentions; 1 submissions, 3 comments2021-01-01 00:00:00 UTC to 2022-01-01 00:00:00 UTC (exclusive): 4 mentions; 0 submissions, 4 comments20212022-01-01 00:00:00 UTC to 2023-01-01 00:00:00 UTC (exclusive): 2 mentions; 0 submissions, 2 comments2023-01-01 00:00:00 UTC to 2024-01-01 00:00:00 UTC (exclusive): 3 mentions; 0 submissions, 3 comments2024-01-01 00:00:00 UTC to 2025-01-01 00:00:00 UTC (exclusive): 3 mentions; 0 submissions, 3 comments2025-01-01 00:00:00 UTC to 2026-01-01 00:00:00 UTC (exclusive): 2 mentions; 1 submissions, 1 comments2026-01-01 00:00:00 UTC to 2027-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments. Incomplete calendar period.2026*

* An incomplete calendar period is marked with an outlined bar. Its count is not directly comparable with a full period.

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges
UTC ranges include their start and exclude their end. Select a period to filter the source evidence.
PeriodStart (UTC)End (exclusive, UTC)MentionsSubmissionsComments
20172017-01-01 00:00:00 UTC2018-01-01 00:00:00 UTC211
20182018-01-01 00:00:00 UTC2019-01-01 00:00:00 UTC1028
20192019-01-01 00:00:00 UTC2020-01-01 00:00:00 UTC936
20202020-01-01 00:00:00 UTC2021-01-01 00:00:00 UTC413
20212021-01-01 00:00:00 UTC2022-01-01 00:00:00 UTC404
20222022-01-01 00:00:00 UTC2023-01-01 00:00:00 UTC202
20232023-01-01 00:00:00 UTC2024-01-01 00:00:00 UTC303
20242024-01-01 00:00:00 UTC2025-01-01 00:00:00 UTC303
20252025-01-01 00:00:00 UTC2026-01-01 00:00:00 UTC211
2026 (partial)2026-01-01 00:00:00 UTC2027-01-01 00:00:00 UTC101

From the project README

An excerpt from the repository, fetched Nov 13, 2026.

Read the project’s introduction
Category Theory For Programmers An unofficial PDF version of "Category Theory For Programmers" by Bartosz Milewski, converted from his blogpost series (with permission!). Buy the book Standard edition in full-color hardcover print Publish date: 12 August, 2019. Based off release tag v1.3.0. See errata-1.3.0 for changes and fixes since print. Scala Edition in paperback Publish date: 12 August, 2019. Based off release tag v1.3.0. See errata-scala for changes and fixes since print. Build the book The building workflow requires Nix. After installing Nix, you need to enable the upcoming "flake" feature which must be enabled manually the time being. This is needed to expose the new Nix commands and flakes support that are hidden behind feature-flags. Afterwards, type nix flake show in the root directory of the project to see all the available versions of this book. Then type nix build .#<edition> to build the edition you want (Scala, OCaml, Reason and their printed versions). For example, to build the Scala edition you'll have to type nix build .#ctfp-scala. For Haskell (the original version) that is just nix build .#ctfp. Upon successful compilation, the PDF file will be placed in the result directory. The command nix develop will provide a shell containing all the required dependencies to build the book manually using the provided Makefile. To build the ctfp-scala edition, just run make ctfp-scala. Contribute Contributors are welcome to contribute to this book by sending pull-requests. Once reviewed, the changes are merged in the main branch and will be incorporated in the next release. Note from Bartosz: I really appreciate all your contributions. You made this book much better than I could have imagined. Thank you! Find the list of contributors on Github. Acknowledgements PDF LaTeX source and the tools to create it are based on the work by Andres Raba. The book content is taken, with permission, from Bartosz Milewski's blogpost series, and adapted to the LaTeX format. The original blog post acknowledgments by Bartosz are consolidated in the Acknowledgments page at the end of the book. License The PDF book, .tex files, and associated images and figures in directories src/fig and src/content are licensed under Creative Commons Attribution-ShareAlike 4.0 International License. The script files scraper.py and others are licensed under GNU General Public License version 3.
Read the full README on GitHub

What Hacker News says

10 sources
bmc7505·Oct 26, 2018
AD is important to understand for ML practitioners in the same way as compilers are important to understand for programmers. You can get away without knowing all the details, but it helps to understand where your gradients come from. However this paper is probably not be a good place to start if you're new to AD. If you want a better introduction, here are a few good resources: Autodidact is a pedagogical implementation of AD: https://github.com/mattjj/autodidact A nice literature review from JMLR: http://www.jmlr.org/papers/volume18/17-468/17-468.pdf This paper reinterprets AD through the lens of category theory, an abstraction for modeling a wide class of problems in math and CS. It provides a language to describe these problems in a simple and powerful way, and is the foundation for a lot of work in functional programming (if you're in
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terested in that kind of stuff). There was a thread on HN recently that discusses why category theory is useful: https://news.ycombinator.com/item?id=18267536 "Category Theory for the Working Hacker" by Philip Wadler is a great talk if you're interested in learning more: https://www.youtube.com/watch?v=gui_SE8rJUM Also recommend checking out Bartosz Milewski's "Category Theory for Programmers": https://github.com/hmemcpy/milewski-ctfp-pdf
In The Simple Essence of Automatic Differentiation [pdf]
louthy·Oct 22, 2018
> is category theory worth learning? Yes. Very much so. Especially if you're programming functionally. It will explain why all this is the way it is. Why sum types and product types are what they are, the big picture on functors, monads, etc, etc. I like Bartosz Milewski's introduction [1][2] where he states (paraphrasing) that he started programming back in the day with assembly, and as programs got more difficult we needed higher level abstractions, so he moved to procedural languages, and then after that another higher abstraction was OO, but he realised that OO has a fundamental problem: objects don't compose, and so he found himself functional programming with Haskell... each time looking for better abstractions. Category Theory is the ultimate abstraction and although you can't write code with it, you can step outside of the de
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tail of complex solutions and think about the bigger picture and then use that bigger picture to help you build your detail. And that's why I think it's valuable. I particularly like his journey too, as it exactly reflects my own. [1] Category Theory for Programmers - https://github.com/hmemcpy/milewski-ctfp-pdf [2] https://www.youtube.com/user/DrBartosz/playlists
In An invitation to category theory

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