frontpage.
newsnewestaskshowjobs

Made with ♥ by @iamnishanth

Open Source @Github

fp.

Open in hackernews

LSP client in Clojure in 200 lines of code

https://vlaaad.github.io/lsp-client-in-200-lines-of-code
164•vlaaad•6mo ago

Comments

whalesalad•6mo ago
This is the most Java-y Clojure I’ve probably ever read. Just use Java? It’s so verbose and complex for what it is doing. Breaking this down into smaller functions and using core.async would make it even more succinct.

Just want to emphasize this because clojure is indeed a small, lesser known language that has a hard enough time attracting users. This is not what anyone would consider an idiomatic example of using clojure.

roenxi•6mo ago
Would it be 200 lines of Java? It'd be 200 lines of just for the boilerplate. It isn't really a selling point of Clojure because it is subjective, but low-syntax high-terseness look of the code is in itself a reward for using the language.

And there isn't anything especially wrong with sticking to Java primitives if someone is comfortable with them. They work fine for Java programmers. The dude doesn't need to learn a new async library to write an LSP client if he doesn't feel like it. Code works, its easy to read, easy to understand and modify.

koito17•6mo ago
Line count is not very useful to compare without the context of standard library size, third-party dependencies, etc. The code in TFA depends[1] on a JSON library[2] that is about a thousand lines of code (excluding tests) wrapping a Java library for JSON decoding.

Then there's other things to consider, like the fact that this LSP client, while succinct, pays not only the cost of loading Jackson, but also the cost of loading clojure.core, which is quite non-trivial[3]. Startup time for LSP servers and clients definitely matters to some, considering that e.g. even clojure-lsp recommends running native executables over JAR files[4]. Can't find documentation proving it's for quick startup, but it's a plausible rationale for their recommendation of a binary over a JAR.

Note: I have used Clojure professionally and in hobby projects. I think it's nice that one can interactively develop a minimal LSP client and the resulting amount of work is roughly 200 lines of code. I say "minimal" because it's unclear how this client deals with offsets reported by LSP servers, which are all given as offsets in a UTF-16 encoded string. In any case, I still think advertising "LSP client in 200 lines of code" hides valuable information regarding functionality, implementation, "actual" code size, and trade-offs made in the choice of technology stack.

[1] https://github.com/vlaaad/lsp-clj-client/blob/a567e66/deps.e...

[2] https://github.com/metosin/jsonista/blob/c8f2b62/project.clj...

[3] https://clojure-goes-fast.com/blog/clojures-slow-start/#cloj...

[4] https://clojure-lsp.io/installation/#embedded-jar-legacy-exe...

pron•6mo ago
Between records and compact classes [1] Java's boilerplate isn't what it once was.

[1]: https://openjdk.org/jeps/512

newlisp•6mo ago
It's idiomatic "low-level" Clojure, though. Not everything is a happy place where you're just manipulating maps and vectors like in most examples.
0x1ceb00da•6mo ago
> lesser known language that has a hard enough time attracting users

For very good reasons.

dig1•6mo ago
I don't see why this wouldn't be considered idiomatic clojure code; it makes proper use of all the facilities provided by the language and the main intention of this code is to follow the article. Additionally, the clojure core team often encourages not to shy away from using java code directly, as this approach strikes a good balance between performance and language expressivity.

> It’s so verbose and complex for what it is doing. ... and using core.async

I think this code is actually quite straightforward and easy for a clojure developer to understand. In fact, using core.async in this case would be overkill and could complicate things further.

daveliepmann•6mo ago
This looks like the other completely normal, idiomatic Clojure programs I've seen which manipulate a StringBuilder. And as Clojurians go I'm far to the succinctness/concision-preferring end of the spectrum.

I'm curious to see your core.async-based version :)

askonomm•6mo ago
Holy crap is this unreadable or what (notably the lsp-base fn). There's a reason why in most Clojure companies I've worked at we try to make as small functions as possible, because otherwise it very very quickly becomes an unreadable mess, and you write code after all for humans to read, because if you didn't, you might as well just write binary. But, I'm not surprised many people don't want to get into Clojure or Lisps in general, because it takes a boatload of conventions and active discipline to make it a good experience.
slifin•6mo ago
To me something unreadable is code that I cannot statically make any assertions about the runtime behaviour of the code

This function you're complaining about looks like 2 virtual threads doing program input reading and output writing for the LSP client given some ArrayBlockingQueues in about 25-30 lines

If I wanted the complete story I could use Clojure's inbuilt test runner to slip some ArrayBlockingQueues in there and run it under record with Flowstorm

Then leisurely seek through the entire state of the program, to get the play-by-play of how this works

There are so many good design choices in this language and a good 30% of colleagues I run into are not even doing the basics of like running a REPL, I think some people just need to clock in with a decade of C# or PHP or TS or JS or Python or whatever to get a taste of a language with next to no inbuilt immutability, statements instead of expressions, no reload-ability in the language semantics and just crapshot debuggers that run in lockstep with the program execution

Presenting the Rust Quotes from the Mozilla QDB

https://brson.github.io/2025/11/21/rust-qdb
1•brson•1m ago•0 comments

AlphaXiv raises $7M in funding to become the GitHub of AI research

https://siliconangle.com/2025/11/19/alphaxiv-raises-7m-funding-become-github-ai-research/
1•gmays•2m ago•0 comments

Fundex: Intelligent CRM Platform Capital Raising and Fund Management

https://www.usefundex.com/
1•JeffreyFco•2m ago•0 comments

We remember the internet bubble. This mania looks and feels the same

https://crazystupidtech.com/2025/11/21/boom-bubble-bust-boom-why-should-ai-be-different/
2•speckx•5m ago•0 comments

The fate of "small" open source

https://simonwillison.net/2025/Nov/17/the-fate-of-small-open-source/
1•synergy20•6m ago•0 comments

Trump peace plan for Ukraine includes NATO-style security guarantee

https://www.axios.com/2025/11/21/ukraine-security-guarantee-nato-article-5-trump
2•MilnerRoute•9m ago•0 comments

Reform UK's former Wales leader jailed for taking bribes for pro-Russia speeches

https://www.theguardian.com/politics/2025/nov/21/nathan-gill-former-reform-uk-wales-leader-jailed...
1•xworld21•10m ago•0 comments

Active Agent: Build AI in Rails

https://docs.activeagents.ai/
2•mooreds•11m ago•0 comments

Show HN: Nemorize – AI-powered spaced repetition for learning anything

https://nemorize.com/
1•reverseblade2•11m ago•0 comments

Show HN: Zo, a Friendly Personal Server

https://www.zo.computer/
1•benzguo•13m ago•0 comments

Understanding QCOW2 Risks with QEMU Cache=None in Proxmox

https://kb.blockbridge.com/technote/proxmox-qemu-cache-none-qcow2/
1•todsacerdoti•13m ago•0 comments

Implementing Custom Autocomplete in VSCode

https://dganev.com/posts/2025-11-18-using-custom-autocomplete/
1•syl5x•14m ago•0 comments

Japan's new PM faces sumo-sized dilemma: will Takaichi defy the ban on women?

https://www.theguardian.com/world/2025/nov/12/japan-pm-sumo-wrestling-ban-women
1•PaulHoule•15m ago•0 comments

Froot Salad: your goal is to guess a hidden combination of 8 froots in 6 guesses

https://frootsalad.com/
2•sebg•16m ago•1 comments

Behind the Curtain: Red Alert – Republicans Fret over American's Dislike of AI

https://www.axios.com/2025/11/20/republicans-trump-maga-2026-recent-polls
2•zerosizedweasle•16m ago•4 comments

Show HN: Gocat – URL shortener using Google Sheets

https://github.com/autokitteh/kittehub/tree/main/gocat
1•itayd•17m ago•0 comments

Japanese Mozilla volunteers quit over AI plans

https://www.quippd.com/writing/2025/11/20/mozilla-support-update-end-of-japanese-community-mozill...
4•ReadCarlBarks•17m ago•0 comments

Ask HN: Why doesn't Hacker News improve its UI?

2•liquid99•18m ago•1 comments

How to Prompt Nano Banana Pro

https://replicate.com/blog/how-to-prompt-nano-banana-pro
3•johnsillings•18m ago•0 comments

US stocks just suffered one of their most stunning reversals in 32 years

https://sherwood.news/markets/us-stocks-just-suffered-one-of-their-most-stunning-reversals-in-32-...
1•avonmach•20m ago•0 comments

PolyAgora v1.0 – A Natural-Language Multi-Axis Cognitive OS (Whitepaper, DOI)

https://zenodo.org/records/17675442
1•takeshi_sakamo•22m ago•0 comments

Token Efficiency

https://www.june.kim/token-efficiency
1•speckx•22m ago•0 comments

Made a tool to detect process injection

https://github.com/pandaadir05/ghost
1•pandaadir05•23m ago•1 comments

The Future of Codewars

https://www.codewars.com/post/the-future-of-codewars-a-message-from-our-ceo
1•captn3m0•23m ago•0 comments

The Battle for the Soul of the University

https://macleans.ca/longforms/the-battle-for-the-soul-of-the-university/
1•binge_thinking•23m ago•0 comments

How PDF became the past, present and future of consent forms

https://formesign.com/fillable/fillable-pdf-to-form-merge.html
1•QueensGambit•27m ago•0 comments

Researcher's Smuggling Arrest Casts Light on Dispute over Chinese Students

https://www.nytimes.com/2025/11/21/world/asia/chinese-students-us.html
1•perihelions•28m ago•0 comments

You can make smells with ultrasound

https://writetobrain.com/olfactory
9•exr0n•33m ago•0 comments

Voxel Duke Nukem 3D

https://www.moddb.com/mods/voxel-duke-nukem-3d/addons/voxel-duke-3d
3•Venn1•34m ago•0 comments

What humans are meant to do

https://maximizinginterest.substack.com/p/what-humans-are-meant-to-do
1•anonisfree•35m ago•0 comments