semantic-source VS typescript-language-server

One production example I know: GitHub code navigation is written in Haskell https://github.com/github/semantic

ah, easy. it's because support has not been added into https://github.com/github/semantic which is the tech that powers the GitHub UI. Adding support is pretty easy/mainly glue code [1] that imports the tree sitter API.

[1] https://github.com/github/semantic/blob/793a876ae45d38a6bd17...

I believe they use semantic (Haskell program that uses tree-sitter) for navigation: https://github.com/github/semantic

So the answer may be that semantic does not yet have support for the language in question.

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

That was interesting, thanks for pointing it out

I was tremendously sad to see that the Typescript Language Server wasn't owned by Microsoft <https://microsoft.github.io/language-server-protocol/impleme...>, since if there was any sanity in the world a spec bump would travel with a reference implementation showing how they envision such a thing being used

But, I found that the Typescript Language Server that they did list does indeed have a semantic-tokens module in it, although it's much shorter than I would have expected from reading that section in the spec: https://github.com/typescript-language-server/typescript-lan...

[[language]] name = "python" roots = ["pyproject.toml"] formatter = { command = "black", args = ["--quiet", "-"] } language-server = { command = "pyright-langserver", args = ["--stdio"] } config = {} auto-format = true [[language]] name = "rust" auto-format = true # [[language]] # name = "typescript" # auto-format = true # formatter = { command = "prettier", args = ["--parser", "typescript"]} # # pass format options according to https://github.com/typescript-language-server/typescript-language-server#workspacedidchangeconfiguration omitting the "[language].format." prefix. # config = { format = { "semicolons" = "insert", "insertSpaceBeforeFunctionParenthesis" = true } } [[language]] name = "tsx" formatter = { command = 'prettier', args = ["--parser", "typescript"] } auto-format = true [[language]] name = "javascript" auto-format = true formatter = { command = 'npx', args = ["prettier", "--config", ".prettierrc", "--parser", "javascript"] } # formatter = { command = "prettier", args = ["--parser", "javascript"]} [[language]] name = "css" formatter = { command = 'prettier', args = ["--parser", "css"] } [[language]] name = "markdown" # https://github.com/executablebooks/mdformat formatter = { command = "mdformat", args = ["-"] } [[language]] name = "json" formatter = { command = "prettier", args = ["--parser", "json"] } [[language]] name = "toml" auto-format = true # https://github.com/bd82/toml-tools/tree/master/packages/prettier-plugin-toml formatter = { command = "prettier", args = ["--parser", "toml"] } [[language]] name = "yaml" indent = { tab-width = 2, unit = " " } formatter = { command = "prettier", args = ["--parser", "yaml"] } [[language]] name = "astro" scope = "source.astro" injection-regex = "astro" file-types = ["astro"] roots = ["package.json", "astro.config.mjs"] language-server = { command = "astro-ls", args = ["--stdio"] } config = { "typescript" = { serverPath = "/Users/matteostara/.nvm/versions/node/v18.16.0/bin/typescript-language-server" }, "environment" = "node" }

Crossposting from github, because the response rate there has been pretty slow: https://github.com/typescript-language-server/typescript-language-server/discussions/730

Depending on the language server version, you may be running into https://github.com/typescript-language-server/typescript-language-server/issues/631. I temporarily fixed it for me by simply sticking with an old enough server build, though judging by the latest typescript-language-server commits a very recent build from master should also work

Before, I was using typescript-language-server as it is LSP compliant but it was slow and lacks the features of what VSCode's implementation has, like extracting functions, constants, types into interfaces or alias and single imports. Auto-completion was also not very predictive as sometimes it works and sometimes it doesn't. For instance, I was having trouble getting it to auto-complete common attributes like className or href in JSX projects. It could be that I may be doing something wrong but didn't find any solution on how to get it properly working.

Then this is highly likely issue of typescript-language-server. You might consider opening an issue for it.

This is not the case! After reading the LSP help pages (:help lsp), I installed and configured two language servers: Typescript Language Server for JavaScript and Pyright for Python. Neovim has fantastic defaults, so things like tags, omnicompletion, and semantic highlighting (New in 0.9) are enabled and configured by default as long as your language server supports them. You can see my configuration below.

Open feature request to typescript-language-server or check corresponding implementaion in vscode and make a pr for it.

Use mason to install tsserver, or directly install it on your computer following typescript-language-server. Note that your javascript's ls is powered by tsserver not eslint since eslint is a linter, not a ls.