C3 LSP

A Language Server Protocol implementation for the C3 programming language, written in C3.

Features

• Go to Definition / Declaration — navigate to functions, types, constants, enum members; supports method calls and cross-file lookup including stdlib
• Find References — find all occurrences of a symbol across open files and project sources
• Rename Symbol — rename identifiers, types, and constants across files
• Hover — view type signatures and doc comments on hover
• Completion — autocomplete for keywords, types, identifiers, compile-time builtins, and attribute names
• Signature Help — parameter hints when calling functions and macros
• Document Symbols — outline of modules, functions, structs, enums, macros, and constants
• Document Highlights — highlight all occurrences of a symbol in the current file
• Semantic Tokens — enhanced syntax highlighting for identifiers, types, functions, macros, and attributes
• Folding Ranges — code folding for braces, imports, and block comments
• Diagnostics — reports errors and warnings from the C3 compiler on save

NB! Uses C3 project.json sources: [], for reference/auto-complete targets, so make sure your project has project.json, for good experience.

Building

Requires the C3 compiler (v0.7.x or later).

# Build
c3c build lsp

# Run tests
c3c test lsp

The binary is output to build/lsp.

Usage

./build/lsp [options]

The server communicates over stdin/stdout using the LSP JSON-RPC protocol.

Options

Flag	Description	Default
--stdlib-path <path>	Path to the C3 standard library	(none)
--compiler-path <path>	Path to the C3 compiler binary	c3c
--diagnostics-delay <ms>	Throttle delay for diagnostics (ms)	2000

Editor Setup

Configure your editor's C3 language extension to use this LSP binary. For VS Code, set the server path in the C3 extension settings.