frontpage.
newsnewestaskshowjobs

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•1y ago
Downloadable: https://zenodo.org/records/15424968/files/deputy-els.pdf

Comments

droideqa•1y 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•1y ago
Pretty readable code
reuben364•1y 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•1y 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•1y 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•1y 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•1y ago
> EMACS elisp

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

wk_end•1y 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.
dang•1y ago
Any URL for this that we can open in a browser (as opposed to the dreaded "Content-Disposition: attachment")?
Jtsummers•1y 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•1y ago
Thanks! I've switched to that above, and put the downloadable link in the top text.
reikonomusha•1y 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•1y 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•1y ago
Well... believe it or not, some have thought of using lisp for AI for quite some time. ;-)
froh•1y 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
fithisux•1y ago
Impressive.
kscarlet•1y 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.

•
1y 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•1y 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)

"As a Language Model": Chat Template Switches LLM Self-Referential Voice

https://arxiv.org/abs/2609.25021
23•yu3zhou4•46m ago•8 comments

Flip Fluid on Flip Dots

https://mitxela.com/projects/flipflip
109•blutack•1d ago•11 comments

OpenAI Feared "Optics" of what might appear on Hacker News

https://authorsguild.org/news/ag-v-openai-top-execs-knew-mass-book-piracy-was-illegal/
245•papergirl•4h ago•205 comments

Does Georgism work? Five years later

https://www.astralcodexten.com/p/does-georgism-work-five-years-later
355•silveraxe93•1d ago•259 comments

Meta Blocks President Lula's Facebook Page, Campaign Ads 2 Weeks from Election

https://www.reddit.com/r/worldnews/comments/1wr3id3/meta_blocks_president_lulas_facebook_page_and/
189•rbanffy•2h ago•103 comments

Go Concurrency Distilled

https://antonz.org/go-concurrency-distilled/
232•chmaynard•20h ago•92 comments

PipePipe: NewPipe hard fork implementing SponsorBlock

https://github.com/InfinityLoop1308/PipePipe
427•Qision•2d ago•231 comments

Finally, A True Blue Rose Exists

https://www.sciencenews.org/article/true-blue-rose-pigment-copigment
14•bookofjoe•1d ago•3 comments

DeepSeek Elastic Compute (DSec)

https://arxiv.org/abs/2609.22978
255•shenli3514•16h ago•85 comments

Show HN: LightCloud – A cloud console organised like file system

https://www.light-cloud.com/
4•yullius•1h ago•1 comments

Improving site performance by shipping more CSS

https://github.blog/engineering/architecture-optimization/improving-site-performance-by-shipping-...
52•torutofu•22h ago•29 comments

Show HN: Reladraw – A diagram language where you decide where to place things

https://github.com/reladraw/reladraw
319•jpwalsh234•18h ago•86 comments

A searchable library of forgotten public-domain film clips from 1915 onward

https://www.movingimagearchive.com/
177•momentmaker•2d ago•26 comments

Biology might not be quantum, but its math is quantumlike

https://www.quantamagazine.org/biology-might-not-be-quantum-but-its-math-is-quantumlike-20260923/
76•pseudolus•2d ago•25 comments

ASML says it sold 'absolutely nothing' in Europe in 2026

https://www.tomshardware.com/tech-industry/semiconductors/asml-says-its-sells-absolutely-nothing-...
295•MC995•1d ago•660 comments

The internet discovers TLA+. Now what?

https://reasonable.io/blog/tla-tutorial/
20•matt_d•5h ago•11 comments

Evolving programming languages in the AI era

https://dashbit.co/blog/evolving-ai-era
103•pjm331•2d ago•60 comments

Fifteen years later, the Apple Cards origin story

https://lexontech.org/fifteen-years-later-the-apple-cards-origin-story
400•ksec•1d ago•103 comments

An agent used DNS to reach an external chatbot

https://alignment.openai.com/misalignment-reports/an-agent-used-dns-to-reach-an-external-chatbot/
106•apsec112•1d ago•107 comments

What is the size of Yemen? (2024)

https://theborys.substack.com/p/what-is-the-size-of-yemen
178•kspacewalk2•8h ago•60 comments

Drawgent: Coding agent on a live Excalidraw canvas

https://tangled.org/yanndegat.tngl.sh/drawgent
156•parasitid•19h ago•42 comments

How I changed teaching after AI managed to do all my homework assignments

https://thelastsoftwareengineer.substack.com/p/how-i-changed-teaching-after-ai-managed
217•azhenley•2d ago•193 comments

Reverse-engineering the Intel 8087's tangent algorithm: more than CORDIC

https://www.righto.com/2026/09/8087-tangent-cordic.html
80•pwg•17h ago•11 comments

Promising discoveries about the potential for life on one of Saturn’s icy moons

https://www.fu-berlin.de/en/presse/informationen/fup/2026/fup_26_116-enceladus-cassini-mikroben-s...
62•geox•1d ago•35 comments

Exploding variance of means of exponentials: least-squares to the rescue

https://francisbach.com/spectral_log_density_estimation/
33•matt_d•1d ago•0 comments

Turning GLM-5.3-Flash into a Jev-like decision model

https://www.privatemode.ai/blog/system-one-from-glm-flash
97•flxflx•19h ago•39 comments

How to keep enjoying programming in a world of LLMs

https://discourse.haskell.org/t/how-to-keep-enjoying-programming-in-a-world-of-llms/14705
234•signa11•1d ago•276 comments

Generate fonts where every LLM token is the same width

https://ampdot.mesh.host/token-space-fonts.html
67•z-mach9•1d ago•13 comments

Modern Object Pascal Introduction for Programmers

https://castle-engine.io/modern_pascal
176•birdculture•2d ago•77 comments

We Should Be Able to Change Our Languages

http://jimmyhmiller.com/change-our-languages
45•surprisetalk•1d ago•23 comments