Top all-time · #2720
Aaron Hsu
Personal blog · sacrideo.usprogramming
Aaron Hsu writes Fastidious Elegance, a personal blog at sacrideo.us about programming. Since 2013, 28 different Hacker News readers have linked it 40 times, most often “Smaller code, Better code (2017)”. It is still writing: the last post was on 2026-09-11, and you can follow it by feed.
Too few sampled comments (15) to say how often HN recommends it.?
Why HN links it
Aaron Hsu's blog covers APL and array programming, the Co-dfns GPU compiler, paper-based programming, OpenBSD on a MacBook, and fountain pen reviews. Commenters cite it as a source on APL and on handwriting.
Summarised by Claude from a sample of 15 HN comments that link here. Each comment is marked recommending, critical or neutral (citing without judging); how this works.
My name is Aaron Hsu, and I'm a computer scientist. I'm changing the way people look at computing and programming languages, what they can do with them, and how they do it.
Most-linked posts?
- Smaller code, Better code (2017)4 people · 5 mentions · first linked 2019-06-16
- Is APL Dead? Not anymore3 people · 3 mentions · first linked 2020-05-02
- /paper-is-dead-long-live-paper-programming/2 people · 2 mentions · first linked 2018-05-29
- Source Code Readability, Elegance, and Complexity2 people · 2 mentions · first linked 2021-07-17
- Un-structured-programming2 people · 2 mentions · first linked 2018-11-03
- Paper is dead, long live paper programming2 people · 2 mentions · first linked 2018-02-24
- Suggestivity and Idioms in APL (2023)2 people · 2 mentions · first linked 2023-05-08
What Hacker News says?
When reading about APL recently, arcfide - the chap working on a GPU compiler - has expressed that he likes APL's terse code because you can throw it away and rewrite it without too much trouble. His compiler is around 750 lines of code after 6 years of development, but[1]: " If you look at the GitHub contributions that I've made, I've made 2967 of about 3000 commits to the compiler source over that time frame. In t…
Comment linking /smaller-code-better-code/
on “Comparing the Same Project in Rust, Haskell, C++, Python, Scala and OCaml”Submitted Paper is dead, long live paper programming as a story · 149 points
HN discussionIt's a perennial but: unit tests are more about how you think and rigourously approach a problem than preventing regression. I'd say if you wrote unit tests and then deleted them, your code would be better for it. Indeed, I often don't commit some of the tests I've written in order to write the code! I'll ship some subset of them. It's a notebook. They serve as a form of living documentation for the code and help in…
Comment linking /the-fallacy-of-unit-testing/
on “Unit Testing Is Overrated”Submitted Smaller Code, Better Code as a story · 137 points
HN discussionR&D Consultant/Developer/Software Engineer | Clinton, New Jersey, USA | ONSITE VISA | Dyalog Labs | Full Time Full Listing: https://www.sacrideo.us/dyalog-is-hiring/ This is an intense, APL-driven position working closely with both Dyalog, Ltd. and one of our major customers as a full-time consultant. You'll be working with both new development and large, legacy application code bases. This position includes extensi…
Comment linking /dyalog-is-hiring/
on “Ask HN: Who is hiring? (September 2018)”Submitted Is APL Dead? Not anymore as a story · 127 points
HN discussionThanks! I honestly haven't developed much of Mesh in Mesh, because it's still early in the 'bootstrap cycle' and due to the parse delay issue mentioned above. It's also not nearly as robust to errors as it should be - text editors and traditional spreadsheets allow the user to 'sketch' ideas as discussed by Aaron Hsu [1]. I'd like to stick to a grid for writing 'functional core' logic, but there's potential to use a…
Comment linking /un-structured-programming/
on “Mesh Spreadsheet”Submitted Getting Started with APL (2017) as a story · 97 points
HN discussionSo it was originally designed by a Harvard Math professor (Kenneth Iverson) as just that. A new mathematical notation to write down. He didn't get tenure (although later got the Turing award for some of that work) so he went to IBM and they actually implemented it. Aaron Hsu has done some blog posts on how he sometimes code using a nice calligraphic pen and paper with APL. https://www.sacrideo.us/paper-is-dead-long-…
Comment linking /paper-is-dead-long-live-paper-programming/
on “Most(ly dead) Influential Programming Languages”Submitted APL in its modern state (2020) as a story · 95 points
HN discussionIndeed. Reminds me of arcfide's Co-dfns compiler: >I think the first copyright on this compiler is around 2011. That's 6 years for 750 LoC. That's about 125 lines of code per year. >But that doesn't tell the whole story. If you look at the GitHub contributions that I've made, I've made 2967 of about 3000 commits to the compiler source over that time frame. In that time I've added roughly 4,062,847 lines of code to t…
Comment linking /smaller-code-better-code/
on “Going Fast Slowly”Submitted APL a Day as a story · 83 points
HN discussionhttps://www.sacrideo.us/paper-is-dead-long-live-paper-progra... I think one thing to consider would be actually using paper. The terseness means you don't really pay a 'retyping' penalty.
Comment linking /paper-is-dead-long-live-paper-programming/
on “APL deserves its renaissance too”Submitted Writing Code to Be Spoken (2019) as a story · 25 points
HN discussionTinkering with APL (Dyalog) gave me one of my most mind-bending programming moments. dismal ← 10⊥(⌈/10⊥⍣¯1⊢) This is the complete solution to addition in the framework of Dismal Arithmetic [1]. The pivotal idea there was the inverse of a function, and "trains". Until that moment of insight, I was fiddling about with dfns, which looks janky in comparison. dismal ← {10(⊤⍣¯1)⍵}∘{⌈/⍵}∘{10(⊥⍣¯1)⍵}⊢ ⍣¯1 is APL for "invers…
Comment linking /decoding-inverses/
on “Tacit programming”Submitted Paper Programming as a story · 6 points
HN discussionIts encouraging to be reminded that still not everyone who uses Apple hardware runs MacOS exclusively. https://sivers.org/openbsd http://www.sacrideo.us/openbsd-on-macbook/ However I have not heard any reports of anyone running an alternative OS on iPhone or iPad hardware. With every passing year I continue to think it would be interesting to observe how users would choose if Apple hardware and Apple software were s…
Comment linking /openbsd-on-macbook/
on “iOS, the Future of MacOS, Freedom, Security and Privacy”Submitted Is APL Dead? as a story · 4 points
HN discussionIts encouraging to be reminded that still not everyone who uses Apple hardware runs MacOS exclusively. https://sivers.org/openbsd http://www.sacrideo.us/openbsd-on-macbook/ However I have not heard any reports of anyone running an alternative OS on iPhone or iPad hardware. With every passing year I continue to think it would be interesting to observe how users would choose if Apple hardware and Apple software were s…
Comment linking /openbsd-on-macbook/
on “iOS, the Future of MacOS, Freedom, Security and Privacy”Submitted Suggestivity and Idioms in APL (2023) as a story · 3 points
HN discussionAaron's been an academic for most of his career and was working for Dyalog as of 2020 (edit: still there, per [0]). I wouldn't describe his work as "production", since it mainly relates to APL itself rather than some external problem to be solved with it. [0] https://www.sacrideo.us/speaking-at-fnconf-22-dsls-architect...
Comment linking /speaking-at-fnconf-22-dsls-architecture-structural-design-in-apl-3-ways/
on “Dyalog APL 18.2”Submitted Smaller code, Better code (2017) as a story · 3 points
HN discussion2014? That dates how long I've had this Sidewinder X4 keyboard from my reply there, and roughly how long my experience with the Datahand and Plover has put me off buying another strange or unusual keyboard. Specifically the "Truly Ergonomic"/Cleave keyboard which came up in the last year or so for another round of production, and when I googled it found a review by Xah Lee [1] - who no longer uses it - and this guy…
Comment linking /not-your-typical-keyboard/
on “DataHand”Submitted Suggestivity and Idioms in APL as a story · 3 points
HN discussion> I'm especially fond of the power (⍣) operator Oh boy, I had a mind-melting moment with _inverse_ (⍣¯1). Aaron helped me understand what was going on. He wrote about "Decoding Inverses" here: https://www.sacrideo.us/decoding-inverses/ And that took me from a clunky solution to Dismal Arithmetic (addition): {10(⊤⍣¯1)⍵}∘ {⌈/⍵}∘ {10(⊥⍣¯1)⍵}⊢ 100000 10000 1000 100 10 1 111111 To this little gem: da ← 10⊥(⌈/10⊥⍣¯1⊢) da…
Comment linking /decoding-inverses/
on “Mastering Dyalog APL (2009) [pdf]”Submitted Testing low-end, affordable pens as a story · 2 points
HN discussionHis APL to GPU compiler is less than 1000 loc in it's entirety and the "comments" are the 400 page accompanying master's thesis. There are a few HN discussions u/arcfide and several YouTube presentations at functional programming conferences. Neat stuff! https://news.ycombinator.com/item?id=13565743 https://www.sacrideo.us/smaller-code-better-code/
Comment linking /smaller-code-better-code/
on “Writing Code to Be Spoken (2019)”Submitted Smaller Code, Better Code as a story · 2 points
HN discussionThen see Aaron Hsu's fountain pen reviews: https://www.sacrideo.us/a-quick-review-of-the-diplomat-nexus... The way this reads is pretty hysterical. I believe he's on here as user "arcfide".
Comment linking /a-quick-review-of-the-diplomat-nexus/
on “The importance of handwriting is now better understood”Submitted Multi-dimensional weighted random roll (choice, dice, selection) as a story · 2 points
HN discussion
