LSP / IDE setup¶

c4 lsp is a JSON-RPC over stdio language server. Capabilities:

Feature	Notes
Diagnostics	parser + resolver + type checker, on save & change
Hover	inferred type / function signature
Go to definition (F12)	function / class / top-level variable
Find references (Shift+F12)	all matching `Name` occurrences
Document symbols (Ctrl+Shift+O)	top-level fns + class methods
Completion (Ctrl+Space, `.`)	scope-aware: params, locals, loop vars, catch bindings; member completion for known shapes (`req.`, `result.`, `log.`, …)
Signature help (after `(`)	resolves user-defined fns and built-ins
Format (Shift+Alt+F)	canonical re-format from AST

VS Code¶

The repository ships an extension at editor/vscode/cobra4.

cd editor/vscode/cobra4
npm install
npx vsce package
code --install-extension cobra4-0.1.0.vsix

Settings:

Setting	Default	Effect
`cobra4.executable`	`c4`	Path to the `c4` CLI (use absolute if not on PATH).
`cobra4.lsp.enabled`	`true`	Run the language server.
`cobra4.format.onSave`	`false`	Run `c4 fmt` on save.
`cobra4.check.strict`	`false`	Pass `--strict` to `c4 check`.

Any LSP-aware editor: point it at the command c4 lsp for files with extension .c4. Communication is plain LSP over stdio.