There was a recent post on Reddit asking why there wasn’t an LSP for Crystal. This is a copy / paste of what I said in response, repeated for visibility and further discussion. There are a number of things that make writing a language server for Crystal difficult. There is no fault tolerant pars…

I think I was originally approaching this of requiring types to get autocomplete, but I think you bring up a really great point I haven’t thought of, and a potentially different way of looking at this problem. In the case of this: def foo(a) b = a.| end I think all possible methods should be au…

IMO explicitly typing everything is a minor inconvenience at worst and leads to safer code in the end, so it’s 100% worth it. Type information on hover is the feature I personally would like the most, for which strict typing is certainly a prerequisite.

I’ve been using GitHub - elbywan/crystalline: A Language Server Protocol implementation for Crystal. 🔮 for a while now. The only issue I’ve had with it is that it slows down over time… I don’t spend much time programming Crystal to invest in debugging this; but it works for my other LSP needs. If …

[image] nobodywasishere: My current approach that some people may not like, is that to get LSP-like features, methods / parameters / variables need to be explicitly typed. It’s the only way to avoid needing a full semantic analysis to resolve types. At first, this made me sad. Then I thought …

I am not familiar with LSP, but something just chocked me about Crystal: Crystal’s complex syntax ??? I would like to understand. Have you got an example ?

[image] Xen: I’m not sure I agree. My method might only require the argument you pass it answer to [](String) with a String, but if I typehint it to Hash(String, String) I limit your options on what you can pass. No passing it a HTTP::Headers, no matter how convenient it might be. I think tha…

[image] straight-shoota: I think that’s a bit of a special case. In quite many cases it’s entirely possible to easily type most parameters. Well, it’s duck typing. And it’s the cases left over from “quite many cases” that I’m thinking about. [image] straight-shoota: Also we can improve c…

[image] Proposal: Interfaces for more generic code Community This is a great idea, and I’d like this to happen. The problem is that interfaces are typed, but in the rest of the language it’s not mandatory to type your methods. So a user will create a type with def to_i w…

Well, maybe in 2.0 then… Anyway, I just wanted to point out that not everybody thinks “just type everything” is all it’s cracked up to be, but I won’t derail the threat further. But an LSP that can complete on variables with known types, and make an educated guess for those without, would be excell…

That is true. There is a middle ground of something closer to type hints rather than type restrictions (see crystal-lang/crystal#15334 ) that I’ve also been thinking about. Things are still too early, the only things that exist currently are semantic tokens using the tree sitter and ameba integratio…

"Why isn't there an LSP for Crystal?"

Crystal Contrib Tooling

nobodywasishere February 7, 2025, 4:24pm 13

Topic		Replies	Views
Crystalline - LSP server for Crystal Community	40	5541	June 10, 2022
Adamas: experimental LSP-first compiler work, current status, and feedback request Tooling	28	493	June 4, 2026
Incremental compilation exploration Crystal Contrib	114	7495	October 13, 2025
Crystal lsp in crystal i Help & Support	4	374	October 16, 2023
Exploring the Compiler Tooling	26	1428	March 8, 2025

"Why isn't there an LSP for Crystal?"

Related topics