Editor support

vct-lsp is a language server for .vct songs. It speaks LSP over stdin/stdout and gives any LSP editor:

• Diagnostics: the parser's errors and warnings as you type, underlining the token at fault (the same checks as vct check).
• Highlighting: semantic tokens from the lexer: header keys and values, section names, lengths, modifiers, strings, markers, lyrics, comments.
• Completion: the song editor's autocomplete: header keys and values, section names (Verse 3 after Verse 2) with a length, modifiers not already on the line, marker and lyric snippets. The part to type over is a snippet placeholder.
• Hover: what a header key or modifier does; on a section, marker or lyric line, where the section falls in the song (bars, start time, tempo, meter). The song has to parse for the second one.
• Outline (document symbols): the headers, then each section with its markers and lyrics. Folding: a section with its markers and lyrics.
• Formatting, on save or on demand: lines the song up in columns, the way examples/example-song.vct is written. Header values in one column; section lengths in a column, then each modifier position in its own; marker and lyric text lined up with the lengths; trailing comments kept in their column where they fit. Only the spaces between words change: names, values, marker text and lyrics stay as written, and if the result would play differently in any way, the file is left alone.

Build it and put it on PATH:

mise run build:vct-lsp
ln -s "$PWD/build/vct-lsp" ~/.local/bin/vct-lsp   # or anywhere on PATH

Neovim (0.11+)

editors/nvim is a plugin directory: filetype detection, ftplugin settings (# comments, two-space indent) and an lsp/vct.lua config that plugin/vct.lua enables. Add it to the runtime path.

With lazy.nvim:

{ dir = "/path/to/StageDisplay/editors/nvim" }

Or in init.lua:

vim.opt.rtp:append("/path/to/StageDisplay/editors/nvim")

If vct-lsp isn't on PATH, point at it:

vim.lsp.config("vct", { cmd = { "/path/to/StageDisplay/build/vct-lsp" } })

Saving a .vct file formats it. To turn that off:

vim.g.vct_format_on_save = false

:lua vim.lsp.buf.format() formats on demand.

Semantic highlighting is on by default. Completion appears through nvim-cmp or blink.cmp if you use one. With neither, turn on the built-in completion:

vim.api.nvim_create_autocmd("LspAttach", {
  callback = function(ev)
    local client = vim.lsp.get_client_by_id(ev.data.client_id)
    if client and client.name == "vct" then
      vim.lsp.completion.enable(true, client.id, ev.buf, { autotrigger = true })
    end
  end,
})

Zed

editors/zed is a Zed extension: the VCT language (.vct, # comments) and a small Rust shim that starts vct-lsp from PATH. To install it: run zed: install dev extension from the command palette and choose editors/zed. Zed compiles the shim itself, so Rust must be installed through rustup.

The extension has no tree-sitter grammar, so its colours come from the server's semantic tokens. Zed turns those off by default; turn them on for VCT in settings.json:

{
  "languages": {
    "VCT": { "semantic_tokens": "full" }
  }
}

Zed formats on save by default, using the language server when there's no other formatter, so saving lines the song up. To be explicit, or to turn it off ("format_on_save": "off"):

{
  "languages": {
    "VCT": {
      "semantic_tokens": "full",
      "format_on_save": "on",
      "formatter": "language_server"
    }
  }
}

editor: format formats on demand.

Other editors

Any LSP client works. Run vct-lsp (it accepts --stdio) for files with the .vct extension. The token types are the standard ones (comment, property, string, class, number, operator, keyword, parameter, variable), so themes colour them without extra setup.