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...

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.

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/

Besides the features TypeScript itself proposed, the most important thing it brought to the community was the ability to create cool features around this compiler that enhance the developer experience and productivity. Tools like tsserver, pretty ts errors, and many others are actively improving the ecosystem for both JavaScript and TypeScript writers.

Sometimes a language server can support multiple filetypes. An example of this is tsserver, the language server for javascript and typescript. In this case a filetype plugin can still work but there is an easier way to go about it.

in this way the ts server can detect and parse the component from the microfronent, thanks to monorepos!

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...

I would like to use svelte language server when working on +page.server.ts files and not the typescript language server.

[[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" }

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.