compact-lsp

⚠️ Note: This is an experimental project developed in my personal free time for educational purposes — primarily to learn how Language Server Protocol implementations work. While functional, it is not officially supported. Feedback and contributions are welcome!

Language Server Protocol implementation for the Compact smart contract language (Midnight network).

Features

Feature	Description
Diagnostics	Real-time syntax errors + compiler errors on save
Semantic Tokens	Rich syntax highlighting (functions, types, parameters, etc.)
Completion	Keywords, types, snippets, local and imported symbols
Hover	Documentation for keywords, types, and symbols
Go to Definition	Jump to symbol definitions (local and imported)
Find References	Find all usages of a symbol (local and cross-file)
Rename	Rename symbols across the workspace
Signature Help	Parameter hints while typing function calls
Document Symbols	Outline view (circuits, structs, enums, modules)
Formatting	Code formatting via format-compact
Folding Ranges	Code folding for blocks and functions
Cross-file Errors	Errors propagate to dependent files on save

Cross-Project Support

Works with Compact's import system:

import "./Utils" prefix Utils_;

Utils_add(5, 5);  // Completion, hover, go-to-def, find refs, rename, signature help all work

Missing Things

Feature	Status
Code Actions	TODO

Requirements

• Rust toolchain (for building)
• compactc compiler (for diagnostics)
• format-compact (optional, for formatting)

Building

cargo build --release

Binary: target/release/compact-lsp

Compiler Location

The LSP auto-detects compactc.bin:

1. COMPACT_COMPILER environment variable
2. ~/compactc/compactc.bin
3. compactc.bin in PATH

Related Projects

• compact.vim - Vim/Neovim syntax highlighting
• compact-tree-sitter - Tree-sitter grammar

Neovim Setup

1. Create LSP config

Create ~/.config/nvim/lua/lsp/compact.lua:

return {
    cmd = { vim.fn.expand("~/path/to/compact-lsp/target/release/compact-lsp") },
    filetypes = { "compact" },
    root_markers = { ".git", "compact.toml", "package.json" },
}

2. Register filetype and enable LSP

Add to your Neovim config:

-- Register .compact filetype
vim.filetype.add({
    extension = { compact = "compact" },
})

-- Load and register compact LSP
local compact_config = require("lsp.compact")
vim.lsp.config("compact_lsp", compact_config)

-- Auto-enable for .compact files
vim.api.nvim_create_autocmd("FileType", {
    pattern = "compact",
    callback = function()
        vim.lsp.enable("compact_lsp")
    end,
})

3. Verify

Open a .compact file and run:

:LspInfo

Optional: Enable semantic highlighting

Add to your config to use LSP semantic tokens for highlighting:

vim.api.nvim_create_autocmd("LspAttach", {
    callback = function(args)
        local client = vim.lsp.get_client_by_id(args.data.client_id)
        if client and client.server_capabilities.semanticTokensProvider then
            vim.lsp.semantic_tokens.start(args.buf, args.data.client_id)
        end
    end,
})

License

MIT