frontpage.
newsnewestaskshowjobs

Made with ♥ by @iamnishanth

Open Source @Github

fp.

Open in hackernews

The Lisp in the Cellar: Dependent types that live upstairs [pdf]

https://zenodo.org/records/15424968
88•todsacerdoti•6mo ago
Downloadable: https://zenodo.org/records/15424968/files/deputy-els.pdf

Comments

droideqa•6mo ago
Sadly "deputy clojure" on Google brings no results...

The only hint is this repo[0] referenced in the paper.

[0]: https://gitlab.com/fredokun/deputy

agumonkey•6mo ago
Pretty readable code
reuben364•6mo ago
Thinking out aloud here.

One pattern that I have frequently used in EMACS elisp is that redefining a top-level value overwrites that value rather than shadowing it. Basically hot reloading. This doesn't work in a dependently typed context as the type of subsequent definitions can depend on values of earlier definitions.

    def t := string
    def x: t := "asdf"
    redef t := int
redefining t here would cause x to fail to type check. So the only options are to either shadow the variable t, or have redefinitions type-check all terms whose types depend on the value being redefined.

Excluding the type-level debugging they mention, I think a lean style language-server is a better approach. Otherwise you are basically using an append-only ed to edit your environment rather than a vi.

extrabajs•6mo ago
I don’t see the connection to dependent types. But anyway, is ‘redef’ part of your language? What type would you give it?
reuben364•6mo ago
I just wrote redef to emphasize that I'm not shadowing the original definition.

    def a := 1
    def f x := a * x
    -- at this point f 1 evaluates to 1
    redef a := 2
    -- at this point f 1 evaluates to 2
But with dependent types, types can depend on prior values (in the previous example the type of x depends on the value t in the most direct way possible, as the type of x is t). If you redefine values, the subsequent definitions may not type-check anymore.
extrabajs•6mo ago
I see what you mean. But would you not experience the same sort of issue simply from redefining types in the same way? It seems this kind of destructive operation (whether on types or terms) is the issue. As someone who's used to ML, it seems strange to allow this kind of thing (instead of simply shadowing), but maybe it's a Lisp thing?
resize2996•6mo ago
> EMACS elisp

I used this to write the front end for an ATM machine.

wk_end•6mo ago
I've fantasized about some kind of a dependently-typed Smalltalk-like thing before, and in those fantasies the solution would be that changes would be submitted in the form of transactions - they wouldn't be live until you bundled them all together into one big change that would be fully type-checked, as you describe.
kscarlet•6mo ago
The only option that you described is called "hyperstatic global environment".

And it is called that for a reason, it is not very dynamic :) and probably too static to the taste of many Lisp and all Smalltalk fans.

dang•6mo ago
Any URL for this that we can open in a browser (as opposed to the dreaded "Content-Disposition: attachment")?
Jtsummers•6mo ago
https://zenodo.org/records/15424968 - This at least takes you to a webpage where you can view the paper. If you select to download it, it still downloads of course instead of just opening in the browser.
dang•6mo ago
Thanks! I've switched to that above, and put the downloadable link in the top text.
reikonomusha•6mo ago
Related context: The 2025 European Lisp Symposium [1] was just wrapped a few hours ago in Zurich. There was content on:

- Static typing a la Haskell with Coalton in Common Lisp

- Dependent typing with Deputy in Clojure (this post)

- The Common Lisp compiler SBCL ported to the Nintendo Switch

- Common Lisp and AI/deep learning

- A special retrospective on Modula and Oberon

- Many lightning talks.

[1] https://european-lisp-symposium.org/2025/index.html

no_wizard•6mo ago
I feel like Lisp would be an ideal language for AI development. Its exceedingly good for DSL development and pattern matching. Its already structurally like math notation as well, which I would think would lend itself to thinking how models would consume information and learn
rscho•6mo ago
Well... believe it or not, some have thought of using lisp for AI for quite some time. ;-)
froh•6mo ago
indeed.

Peter Norvig, 1992

Paradigms of AI Programming: Case Studies in Common Lisp

https://g.co/kgs/hck8wsE

https://en.m.wikipedia.org/wiki/Peter_Norvig

it's no coincidence Google is actively maintaining sbcl, either.

Zambyte•6mo ago
Why not go all the way to the source? John McCarthy coined the term "artificial intelligence", and then invented / discovered LISP in pursuit of it in the 1950s :D
ayrtondesozzla•6mo ago
https://quantumzeitgeist.com/lisp-and-the-dawn-of-artificial...

Lisp was the de facto language of artificial intelligence in the U.S. for many years. Apparently Prolog was popular in Europe (according to Norvig's PAIP)

fithisux•6mo ago
Impressive.

Adafruit: Arduino’s Rules Are ‘Incompatible With Open Source’

https://thenewstack.io/adafruit-arduinos-rules-are-incompatible-with-open-source/
302•MilnerRoute•19h ago•146 comments

DNA Learning Center: Mechanism of Replication 3D Animation

https://dnalc.cshl.edu/resources/3d/04-mechanism-of-replication-advanced.html
19•timschmidt•1w ago•6 comments

Roomba maker goes bankrupt, Chinese owner emerges

https://news.bloomberglaw.com/bankruptcy-law/robot-vacuum-roomba-maker-files-for-bankruptcy-after...
338•nreece•13h ago•389 comments

Unscii

http://viznut.fi/unscii/
188•Levitating•10h ago•20 comments

Arborium: Tree-sitter code highlighting with Native and WASM targets

https://arborium.bearcove.eu/
160•zdw•10h ago•24 comments

If AI replaces workers, should it also pay taxes?

https://english.elpais.com/technology/2025-11-30/if-ai-replaces-workers-should-it-also-pay-taxes....
252•PaulHoule•14h ago•413 comments

Ask HN: What Are You Working On? (December 2025)

320•david927•21h ago•1034 comments

Largest U.S. Recycling Project to Extend Landfill Life for Virginia Residents

https://ampsortation.com/articles/largest-us-recycling-project-spsa
11•mooreds•2h ago•10 comments

Invader: Where to Spot the 8-Bit Street Art in London

https://londonist.com/london/art-and-photography/invader-where-to-spot-the-8-bit-street-art-in-lo...
23•zeristor•1w ago•8 comments

Optery (YC W22) Hiring CISO, Release Manager, Tech Lead (Node), Full Stack Eng

https://www.optery.com/careers/
1•beyondd•2h ago

$5 whale listening hydrophone making workshop

https://exclav.es/2025/08/03/dinacon-2025-passive-acoustic-listening/
61•gsf_emergency_6•4d ago•22 comments

Rob Reiner has died

https://www.hollywoodreporter.com/movies/movie-news/rob-reiner-dead-harry-met-sally-princess-brid...
177•RickJWagner•10h ago•72 comments

AI agents are starting to eat SaaS

https://martinalderson.com/posts/ai-agents-are-starting-to-eat-saas/
212•jnord•14h ago•224 comments

John Varley has died

http://floggingbabel.blogspot.com/2025/12/john-varley-1947-2025.html
109•decimalenough•11h ago•40 comments

The Problem of Teaching Physics in Latin America (1963)

https://calteches.library.caltech.edu/46/2/LatinAmerica.htm
66•rramadass•17h ago•49 comments

The Java Ring: A Wearable Computer (1998)

https://www.nngroup.com/articles/javaring-wearable-computer/
18•cromulent•5d ago•15 comments

Show HN: I wrote a book – Debugging TypeScript Applications (in beta)

https://pragprog.com/titles/aodjs/debugging-typescript-applications/
32•ozornin•1w ago•12 comments

The History of Xerox

https://www.abortretry.fail/p/the-history-of-xerox
45•rbanffy•3d ago•10 comments

Common Rust Lifetime Misconceptions

https://github.com/pretzelhammer/rust-blog/blob/master/posts/common-rust-lifetime-misconceptions.md
64•CafeRacer•8h ago•21 comments

Hashcards: A plain-text spaced repetition system

https://borretti.me/article/hashcards-plain-text-spaced-repetition
350•thomascountz•21h ago•156 comments

CapROS: Capability-Based Reliable Operating System

https://www.capros.org/
94•gjvc•13h ago•36 comments

JSDoc is TypeScript

https://culi.bearblog.dev/jsdoc-is-typescript/
182•culi•18h ago•212 comments

A trip through the Graphics Pipeline (2011)

https://fgiesen.wordpress.com/2011/07/09/a-trip-through-the-graphics-pipeline-2011-index/
19•kruuuder•4d ago•3 comments

Rio de Janeiro's talipot palm trees bloom for the first and only time

https://apnews.com/article/brazil-rio-talipot-palm-flamengo-park-dcfb1ce237af7a10ab72205fc9bbdc02
193•1659447091•1w ago•39 comments

Running on Empty: Copper

https://thehonestsorcerer.substack.com/p/running-on-empty-copper
78•the-needful•6d ago•52 comments

Read Something Wonderful

https://readsomethingwonderful.com/
149•snorbleck•10h ago•28 comments

Elevated errors across many models

https://status.claude.com/incidents/9g6qpr72ttbr
309•pablo24602•16h ago•146 comments

An attempt to articulate Forth's practical strengths and eternal usefulness

https://im-just-lee.ing/forth-why-cb234c03.txt
72•todsacerdoti•1w ago•39 comments

In the Beginning was the Command Line (1999)

https://web.stanford.edu/class/cs81n/command.txt
168•wseqyrku•1w ago•83 comments

The Whole App is a Blob

https://drobinin.com/posts/the-whole-app-is-a-blob/
111•valzevul•10h ago•67 comments