6 engineers on Hacker News describe using J first-hand: 2 endorse it, 1 regret it, 1 are mixed.
“J and APL entered my life over 8 years ago, and I am hooked!”
endorse · personal · 8 yr · eggy · 2021-12-23 · source ↗ · wrong label?“We use J in all ML and data handling functions, everything except UI and viz.”
endorse · production · jpf0 · 2020-08-18 · source ↗ · wrong label?“The error messages can be quite inscrutable sometimes... overall J is a charming (if quirky) language, and well suited for a bit of low-risk exploratory programming.”
mixed · personal · gmfawcett · 2019-12-16 · source ↗ · wrong label?“I paid the price to learn the vocabulary and grammar, but I don't think the language is worth the effort.”
regret · personal · barbudorojo · 2014-11-14 · source ↗ · wrong label?“I have definitely not memorized all of those crazy verbs yet!”
neutral · personal · gmfawcett · 2019-12-16 · source ↗ · wrong label?“I have an outstanding code editor and development environments for Lisp, Scheme, Python, J, F# and JavaScript.”
neutral · personal · taylodl · 2012-11-25 · source ↗ · wrong label?