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Lisp Koans

github.com Books & learning Tutorials & guides Software engineering Candidate
Screenshot of github.com captured 2026-07-20
Page preview · captured 2026-07-20

Resurfaced independently across 6 calendar years, with breakout response in 4 of them.

submissions
7
submitters
7
observed span
2013–2024
peak thread · 33 comments
156 pts
latest 20+ return · 2020-11-28
156 pts

Submission timeline

2007–2026

One slot for every year since HN launched. Height is that year's peak points; orange marks a 100+ point or 50+ comment breakout. Select a bar to open its strongest thread.

First comments on top threads

HN comment order

If you've seen the Lisp Koans in the past, you might want to revisit them someday. Around half a year ago I've rewritten[0] the original set of koans, fixed multiple correctness issues, added some content, and cleaned up the test framework; they now look much better than the original version. [0] https://github.com/google/lisp-koans/pull/111

Currently working through these to learn Common Lisp after being introduced to the language as part of a college CS class, can definitely recommend them along with Practical Common Lisp [0] and Let Over Lambda [1]. 0: http://www.gigamonkeys.com/book/ 1: https://letoverlambda.com/

This is mildly interesting coming out of google because I thought lisp wasn't a google-approved language. (Yes, there are other projects on github in non-approved languages, but they appear mostly to allow 3rd party interop with google services. The educational nature of this project puts it in a slightly different category.)

IvyMike·125-point thread·

I'm surprised to see that this is on Google's Github page. Do they have any projects (besides this) that use Common Lisp?

ihuman·100-point thread·

The first top-level comment from each of the four biggest threads, in HN’s own order. Excerpts are shortened; open a comment for full context.

Breakout years
4

100+ points or 50+ comments

Total points
535

reference only — not used in Hall rules or ranking

Total comments
118

reference only — not used in Hall rules or ranking

Every submission

DateTitle as submittedByPointsComments
2013-06-01Lisp Koans by GoogleFirst breakoutjuanfatas12530
2013-09-18Common Lisp Koansmomo-reina10
2015-12-18Common Lisp Koansgalois19810022
2019-03-05Common Lisp Koansbibyte15133
2020-11-28Lisp KoansBest thread · Latest 20+ point returnphoe-krk15633
2022-03-05Lisp Koansgraderjs10
2024-06-11Common Lisp Koans (2022)nequo10