jphfmt for editors

A Language Server Protocol implementation that formats C with jphfmt, plus a thin VS Code client. The server is a plain stdio LSP, so it works in any LSP-capable editor — VS Code, Neovim, Emacs, Helix — not just VS Code.

It implements one capability, textDocument/formatting: it pipes the document through the jphfmt binary and returns a single full-document edit (or none, when the file is already formatted). Formatting that fails surfaces as an editor error notification; it never returns a partial edit.

Build

npm install
npm run build      # tsc → out/
npm run check      # strict type-check only

jphfmt must be on PATH (or set jphfmt.path). Build it from the repo root with cargo build --release; the binary is target/release/jphfmt.

VS Code

Open this folder in VS Code and press F5 (Extension Development Host), or package with npx vsce package and install the .vsix. Settings:

• jphfmt.path — path to the jphfmt executable (default jphfmt).
• jphfmt.width — column limit (default 100).

Format with the usual Format Document command; enable Format on Save to run it automatically.

Other editors (standalone server)

Run the server over stdio and point your client at it:

node out/server.js --stdio

Pass settings via the client's initializationOptions, e.g. { "path": "/usr/local/bin/jphfmt", "width": 100 }. Example for Neovim's built-in LSP:

vim.lsp.start({
  name = "jphfmt",
  cmd = { "node", "/path/to/out/server.js", "--stdio" },
  init_options = { path = "jphfmt", width = 100 },
  filetypes = { "c" },
})

Layout

• src/jphfmt.ts — the jphfmt subprocess wrapper (a tagged FormatResult).
• src/server.ts — the LSP server (textDocument/formatting).
• src/extension.ts — the VS Code client that launches the server.