robpike
ivy
Go2014–2026
robpike / ivy
ivy
ivy, an APL-like calculator
25Distinct people
30Mentions
0Explicit recommenders
1.5KGitHub stars
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What it is
ivy, an APL-like calculator
GitHub
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This week on Hacker News
Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 3:56:07 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 year30 dated mentions
Observed mentions: 2014-12-11 18:30:52 UTC to 2026-04-14 13:22:07 UTC.
* 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
| Period | Start (UTC) | End (exclusive, UTC) | Mentions | Submissions | Comments |
|---|---|---|---|---|---|
| 2014 | 2014-01-01 00:00:00 UTC | 2015-01-01 00:00:00 UTC | 4 | 1 | 3 |
| 2015 | 2015-01-01 00:00:00 UTC | 2016-01-01 00:00:00 UTC | 3 | 0 | 3 |
| 2016 | 2016-01-01 00:00:00 UTC | 2017-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2017 | 2017-01-01 00:00:00 UTC | 2018-01-01 00:00:00 UTC | 1 | 0 | 1 |
| 2018 | 2018-01-01 00:00:00 UTC | 2019-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2019 | 2019-01-01 00:00:00 UTC | 2020-01-01 00:00:00 UTC | 3 | 1 | 2 |
| 2020 | 2020-01-01 00:00:00 UTC | 2021-01-01 00:00:00 UTC | 3 | 1 | 2 |
| 2021 | 2021-01-01 00:00:00 UTC | 2022-01-01 00:00:00 UTC | 1 | 1 | 0 |
| 2022 | 2022-01-01 00:00:00 UTC | 2023-01-01 00:00:00 UTC | 7 | 2 | 5 |
| 2023 | 2023-01-01 00:00:00 UTC | 2024-01-01 00:00:00 UTC | 3 | 1 | 2 |
| 2024 | 2024-01-01 00:00:00 UTC | 2025-01-01 00:00:00 UTC | 2 | 0 | 2 |
| 2025 | 2025-01-01 00:00:00 UTC | 2026-01-01 00:00:00 UTC | 2 | 0 | 2 |
| 2026 (partial) | 2026-01-01 00:00:00 UTC | 2027-01-01 00:00:00 UTC | 1 | 1 | 0 |
From the project README
An excerpt from the repository, fetched Nov 13, 2026.
Read the project’s introduction
ivy
Ivy is an interpreter for an APL-like language. It is a plaything and a work in
progress.
Ivy has a custom domain. Do not install using github directly. Instead, run:
go install robpike.io/ivy@latest
Documentation at https://pkg.go.dev/robpike.io/ivy.
Try the demo: within ivy, type
)demo
Prototype apps for iOS and Android are available in the App store and Google Play store.
(At the moment, the iOS one is unavailable but will return.)
These are very old but should be updated before too long.
To find them, search for "ivy bignum calculator".
Slides for a talk at: https://talks.godoc.org/github.com/robpike/ivy/talks/ivy.slide
Video for the talk at: https://www.youtube.com/watch?v=PXoG0WX0r_E
The talk predates a lot of the features, including floating point, text, and user-defined operators.
To be built, ivy requires Go 1.24.
Read the full README on GitHubWhat Hacker News says
30 sourcesI think so, or at least something like that. In https://www.arraycast.com/episodes/episode60-rob-pike he mentioned that he has now been working more on Ivy (https://github.com/robpike/ivy) in his spare time.
In Rob Pike goes nuclear over GenAIIvy does big numbers (not arbitrary) but does rationals too. It's an APL subset.
0.1 + 0.2
3/10
https://github.com/robpike/ivy
In Show HN: val – An arbitrary precision calculator languageRuss has indeed been involved, he's done various videos solving advent of code using Ivy.
Russ has also got a pull request to add an operator, see https://github.com/robpike/ivy/pull/83
In Russ Cox is stepping down as the Go tech leadI think you might be thinking of Rob Pike's project, unless Russ has been involved?
https://github.com/robpike/ivy
In Russ Cox is stepping down as the Go tech leadMy recent exposure to array programming languages came via a podcast called The Array Cast[1]
Not affiliated, just recommending. The regular co-hosts appear to each be experienced with various array languages such as J, APL, etc. They don't get deeply technical, but it's a nice introduction, especially on explaining the appeal.
A recent episode had Rob Pike (UTF-8, Go, etc.) on to talk about his array based calculator, Ivy[2]
[1] https://www.arraycast.com/
[2] https://github.com/robpike/ivy
In Uiua: A minimal stack-based, array-based languagehttps://github.com/robpike/ivy
Documentation: https://pkg.go.dev/robpike.io/ivy#pkg-overview
Also see these Advent of Code 2021 solutions with Ivy: https://www.youtube.com/playlist?list=PLrwpzH1_9ufMLOB6BAdzO...
In APL: An Array Oriented Programming Language (2018)I like Ivy's[0] approach by using keywords instead of symbols. I feel like something like APL should either be embedded in some host language, be given lots of functionality for I/O, or some static type system with rank polymorphism.
[0]: https://github.com/robpike/ivy
In APL deserves its renaissance too (2018)Speaking for myself, I find that whenever I think "I just can't see how..." it makes me want to figure out what it is that others can see that I can't. This is the reason I learnt APL, actually, after seeing half a page of k code and feeling annoyed that I couldn't read it. k subsequently led me to APL.
You can try it for yourself -- NumPy is a fair "Iverson ghost" -- APL without the symbols: it has a similar enough array model, and most of the APL primitives as functions or methods. APL lets you express linear algebra in a very natural way. Doing it in NumPy is much more convoluted.
Or try Rob Pike's (of Go fame) "ivy" -- his attempt at an APL-with-words (https://github.com/robpike/ivy).
In APL deserves its renaissance too (2018)I enjoyed russ cox's advent of code series using rob pike's ivy (https://github.com/robpike/ivy), an apl-like calculator
https://www.youtube.com/playlist?list=PLrwpzH1_9ufMLOB6BAdzO...
In APL deserves its renaissance too (2018)Ivy is another APL like language and one I kind of enjoy, because source code is actually readable and writable.
https://github.com/robpike/ivy
In BQN: Finally, an APL for your flying saucerI really like Ivy as a simple, friendly introduction to APL. There is a surprising lack of APL-derived languages that use words to name things -- most stick with the original symbols; J and friends choose equally-cryptic symbols composed of ASCII characters.
Earlier this year I decided to solve AoC 2021 in Ivy, then watch Russ Cox's videos to see how he did it and use that to learn something about array programming -- a topic I knew absolutely nothing about going into this.
Unfortunately, Ivy really is, as Rob Pike says, a plaything. It is buggy -- if you ever write a function that returns a vector or a higher-rank array, you are entering bizarre undefined behavior territory. The array-language equivalent of "concat_map" or "flat_map" or "mapcat" or whatever you want to call it just produces garbage values, which is very confusing when yo
Read the rest
u're learning about array programming for the first time ("Wait, this vector says its length is 25, but it contains 50 elements...?" or "The transpose of this array is just the first column repeated over and over??").
Beyond that, a very cool thing about array languages is that, you know, functions can implicitly act on entire arrays. You can multiple a vector by 2 and it will know to multiply every element in the vector by 2, because multiplication is defined for scalars.
But in Ivy, this is only true for the built-in functions. There is no way to write user-defined functions that have this implicit act-on-every-element behavior. Which is basically the looping primitive in array languages -- so to do anything nontrivial, you have to write it out with explicit recursion (still with the caveat that your functions can only return scalars, or you enter undefined behavior town) or rewrite your operations as binary operations with an ignored right-hand side and use "fold" to "map" them. It's bad.
The latter is crippling enough that Russ Cox eventually forks Ivy to add support for it, but it is not currently part of the language. https://github.com/robpike/ivy/pull/83
Anyway that's a long comment to say: Ivy is a good, friendly introduction to APL syntax (stranding, ambivalent functions, precedence, etc) and some array language concepts, but it is far more of a calculator than a programming language.
But it's a good arbitrary-precision calculator! And if you're still interested in trying it, maybe check out this thing I made. It's an... Ivy programming environment?... that lets you run Ivy scripts and see the results inline. (Ivy's repl is... very primitive, and has to be wrapped by something like readline. Russ Cox uses 9term to get around this; self-modifying programs are my preferred approach.)
https://github.com/ianthehenry/privy
My frustration with Ivy led me to look into other array languages, trying to find one that 1) used English words instead of cryptic symbols and 2) worked. And I really couldn't find any! Someone should do something about that. :)
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