Neovim Integration

Neovim integration has two separate pieces:

• Tree-sitter for syntax/highlighting/queries
• LSP for diagnostics and semantic editor features

They should be configured together, but they do different jobs.

LSP Setup

The language server command is:

vim.lsp.config("fol", {
  cmd = { "fol", "tool", "lsp" },
  filetypes = { "fol" },
  root_markers = { "fol.work.yaml", "build.fol", ".git" },
})

vim.lsp.enable("fol")

Also ensure Neovim recognizes .fol files:

vim.filetype.add({
  extension = { fol = "fol" },
})

Tree-sitter Setup

First generate a bundle:

fol tool tree generate /tmp/fol

Then point Neovim’s Tree-sitter parser config at that bundle:

local parser_config = require("nvim-treesitter.parsers").get_parser_configs()

parser_config.fol = {
  install_info = {
    url = "/tmp/fol",
    files = { "src/parser.c" },
    requires_generate_from_grammar = false,
  },
  filetype = "fol",
}

The query files are expected at:

• /tmp/fol/queries/fol/highlights.scm
• /tmp/fol/queries/fol/locals.scm
• /tmp/fol/queries/fol/symbols.scm

Neovim also needs that bundle on runtimepath so it can find the queries.

Practical Model

Tree-sitter provides:

• highlight captures
• locals captures
• symbol-style structure queries

LSP provides:

• diagnostics
• hover
• definitions
• references
• rename for same-file local and current-package top-level symbols
• semantic tokens
• document symbols

So the normal editor shape is:

1. Neovim opens a .fol file
2. Tree-sitter handles syntax/highlighting
3. Neovim launches fol tool lsp
4. the server provides semantic editor features

Debugging A Setup

Useful checks:

:echo &filetype
:lua print(vim.inspect(vim.lsp.get_clients({ bufnr = 0 })))

And from the shell:

fol tool tree generate /tmp/fol
fol tool lsp

If fol tool lsp prints nothing and waits, that is correct.

It is a stdio server, not an interactive shell command.

If the server refuses to start, check that Neovim opened the file inside a directory tree that contains build.fol or fol.work.yaml.