latform-lsp (language server)¶

latform-lsp is a Language Server Protocol implementation for Bmad lattice files. It brings latform's parsing, formatting, and linting into your editor as you type.

The server is an optional feature — it depends on pygls and is installed with the lsp extra:

pip install "latform[lsp]"

Features¶

Go to definition / find references for elements, lines, and constants
Hover with element type and attribute information
Completion of element names, types, and attributes
Rename (with prepare-rename) across the loaded files
Formatting — whole-document and range, using the same formatter as latform
Document & workspace symbols
Semantic highlighting (semantic tokens)
Code actions
Diagnostics from the same lint rules as latform-lint, including the Tao tao.init namelist checks (LF011–LF014)

The server reads your project's latform.toml / pyproject.toml (see Configuration) and watches those files, so in-editor formatting and diagnostics match what the CLI produces. It applies to *.bmad, *.lat, and tao.init files.

Running¶

latform-lsp communicates over stdio and is normally launched by an editor, not by hand:

latform-lsp [--log-level {debug,info,warning,error,critical}]
            [--log-file PATH] [--no-client-log] [--stdio]

Option	Description
`--log-level`	Logging verbosity (default: `warning`, or `$LATFORM_LSP_LOG_LEVEL`)
`--log-file`	Write logs to this file instead of stderr (or `$LATFORM_LSP_LOG_FILE`)
`--no-client-log`	Do not mirror log messages to the client via `window/logMessage`
`--stdio`	Communicate over stdio (the default and only transport; accepted if a client passes it)

Unrecognized flags a client injects (e.g. --clientProcessId=...) are ignored.

Editor plugins¶

Ready-made clients that discover latform-lsp and register the Bmad filetype:

Editor	Plugin
VS Code	ken-lauer/latform-vscode
Vim	ken-lauer/vim-latform
Neovim	ken-lauer/latform-lsp.nvim

Each still needs latform-lsp available on PATH (pip install "latform[lsp]"); see the plugin's own README for install and configuration details.

Manual setup¶

Any LSP client works — point it at the latform-lsp command over stdio, associated with your Bmad files. The examples below are for when you are not using one of the plugins above.

Neovim¶

Using the built-in LSP client (Neovim 0.11+). latform is not in nvim-lspconfig's registry, so register it yourself:

vim.filetype.add({
  extension = { bmad = "bmad", lat = "bmad" },
  filename = { ["tao.init"] = "bmad" },
})

vim.lsp.config("latform", {
  cmd = { "latform-lsp" },
  filetypes = { "bmad" },
  root_markers = { "latform.toml", "pyproject.toml", "tao.init", ".git" },
})
vim.lsp.enable("latform")

Vim¶

With vim-lsp (or yegappan/lsp, or coc.nvim):

augroup latform_ft
  autocmd!
  autocmd BufRead,BufNewFile *.bmad,*.lat,tao.init setfiletype bmad
augroup END

if executable('latform-lsp')
  autocmd User lsp_setup call lsp#register_server({
    \ 'name': 'latform',
    \ 'cmd': {server_info->['latform-lsp']},
    \ 'allowlist': ['bmad'],
    \ })
endif

VS Code¶

Beyond the latform-vscode extension, you can wire the server into any client built on vscode-languageclient, spawning latform-lsp as a stdio server for the bmad language.

Other editors¶

See the LSP project's list of client implementations.