mclsp 0.5.1

McCode DSL language server (LSP) for .instr and .comp files

mclsp — McCode DSL Language Server

A Language Server Protocol implementation for the McCode domain-specific languages: McStas (.instr, .comp) and McXtrace (.instr, .comp).

Built on top of mccode-antlr and pygls.

Features

Feature	Status
Syntax error diagnostics	✅
Keyword completion	✅
Component name completion	✅
Parameter completion inside Component(…)	✅
Hover: component signature & description	✅
Syntax highlighting (TextMate grammar)	✅
Go-to-definition of .comp files	✅

Installation

pip install mclsp
# or
conda install -c conda-forge mclsp

Editor setup

VS Code

Install the McCode extension from the Marketplace (it bundles mclsp), or point the generic LSP client extension at mclsp --stdio.

A minimal extension stub is provided in vscode-extension/.

Neovim (nvim-lspconfig)

require('lspconfig').mclsp.setup {}

A config will be submitted upstream to nvim-lspconfig once the server stabilises.

Helix

Add to ~/.config/helix/languages.toml:

[[language]]
name = "mccode"
scope = "source.mccode"
file-types = ["instr", "comp"]
language-servers = ["mclsp"]

[language-server.mclsp]
command = "mclsp"
args = ["--stdio"]

Running the server manually

mclsp --stdio          # communicate over stdin/stdout (standard LSP mode)
mclsp --tcp 2087       # listen on TCP port 2087 (useful for debugging)

Development

git clone https://github.com/mcdotstar/mccode-language-server.git mclsp
cd mclsp
uv sync
uv run pytest