semantic-source VS typescript-language-server

GitHub used Haskell for implementing Semantic, a command-line tool for parsing, analyzing, and comparing source code.

As far as engineering effort, you can read this GitHub comment for an overview of where we’d like to take the project in the future. The tl;dr here is that the open sum type view of the world made it very concise to fold over syntax trees (since such a view of data is ultimately unityped, recursion schemes Just Work), but the tradeoff thus associated—namely, that you have to parse a concrete syntax tree into an open-sum view (a complicated and painful-to-read process), that you can never really be sure how a given syntax tree is shaped, and that the types don’t help you nearly as much as they could—proved to be too onerous to deal with. Going forward, we’re generating syntax types from the AST once per target language, and working on an abstraction (probably via this generated code; I made five separate efforts at using Generics for this, and failed every time) that recovers at least some of the convenience of recursion schemes. It turns out that recursion schemes over a mutually recursive syntax tree—as pretty much every language’s syntax trees are, in practice—are pretty much an unsolved problem, especially when extended to languages like TypeScript, which have hundreds of different syntax nodes.

I'm just curious. It seems there hasn't been much activity in https://github.com/github/semantic Is GitHub still using semantic it to power some code navigation features? Has it been abandoned or is there some successor project that has taken its place? Is there any writeup / lessons learned about this project?

is this from Github semantic (https://github.com/github/semantic)?

Seems very suspicious since it’s the same goal using the same technologies. The latest commit is 4mo ago but i assume they have a closed-source version they’ve been working on.

Meanwhile their Tree-Sitter-based semantic parser[1] looks abandoned. There is even rotting for years pull request[2] adding support of the same stack graphs into it.

[1] https://github.com/github/semantic

[2] https://github.com/github/semantic/pull/535

The semantic team at GitHub uses it for statically analyzing the dozens of languages that end up in GitHub repositories: https://github.com/github/semantic/blob/eaf13783838861fe5eb6cd46d59354774a8eb88d/docs/why-haskell.md

Yesterday I was looking for some examples of projects using tree-sitter (which is C) when I found GitHub's semantic, used to analyze and compare source code, and written in Haskell: https://github.com/github/semantic/

Does anyone here have experience with tree-sitter? If you aren't familiar, tree-sitter is a parser generator tool that builds parsers to use with an incremental parsing library. It's what's responsible for AST parsing on GitHub, for instance.

You might want to put some examples of how exactly to use gleam (maybe a 1-2-3 type fashion?) on the front page if possible. This project seems like github/semantic or possibly even more advanced (given that it comes with it's own query language and a shell) but I just can't figure out exactly how I'd use it exactly.

What about https://github.com/github/semantic

Every since this pr https://github.com/typescript-language-server/typescript-language-server/pull/303 got merged, typescript-language-server support function parameters completion. It works in neovim. But doesn't in emacs . Has anyone managed or tried to get it working?

One thing I have difficulty understanding is that given MS is (was?) the primary proponent of LSP, why do community projects like typescript-language-server need to exist ?

Why can't arbitrary LSP clients connect directly to tsserver (maintained by MS) ?

[1] https://github.com/typescript-language-server/typescript-lan...

tsserver doesn't support LSP directly and was written before LSP. typescript-language-server is a translation layer on top of tsserver. Coc's coc-server is a port of VS Code's tsserver adapter plugin, which uses tsserver's native protocol (not LSP).

I hope it worked also with typescript-language-server on loading project. Doesn't it support LSP Progress?(I found this PR but I'm not sure it's that we need)

So you probably need to set some formatting options on tsserver. As I can see from (typescript-language-server doc)[https://github.com/typescript-language-server/typescript-language-server], you can set [language].format.tabSize option there.

I'm using the lspconfig with typescript-language-server and imports work automatically for me when I select an autosuggested item from another module

No idea, I didn't see any options for it. It doesn't really matter anymore, as we can handle it now, but if people are interested you can always file issues upstream https://github.com/typescript-language-server/typescript-language-server/issues

Have you looked at the official ts language server? https://github.com/typescript-language-server/typescript-language-server

The Theia IDE people have implemented a LSP-wrapper around tsserver [1], which works all right. Of course, the reason that Typescript does not comply to the spec is that it was built before the LSP existed.

[1] https://github.com/theia-ide/typescript-language-server

Typescript server support is not as good as coc.nvim, we have to use the theia-wrapper around tsserver because it is non-standard/does not follow the LSP specification. I'm currently looking into some performance implications unique to theia and will likely have news soon, but I don't use javascript.