Useful neovim autocommands for TLA+

autocommands.lua

local function moduleline() -- can't be a global as line can move
  local lines = vim.api.nvim_buf_get_lines(0, 0, -1, false)
  for idx, line in ipairs(lines) do
    if string.match(line, "%-+ MODULE [%w_]+ %-") then
      return idx, line
    end
  end
end

local function fix_module_string()
  local module_string = string.format("---- MODULE %s ----", vim.fn.expand("%:r"))
  local idx, _ = moduleline()
  vim.api.nvim_buf_set_lines(0, idx-1, idx, false, {module_string})
end

local group = vim.api.nvim_create_augroup("tla.custom", { clear = true })

-- Automatically put the module header and footer in new files
vim.api.nvim_create_autocmd({ "BufNewFile" }, {
    pattern = { "*.tla" },
    callback = function()
       local top = string.format("---- MODULE %s ----", vim.fn.expand("%:r"))
       local snippet = {top, "", "===="}
       vim.api.nvim_buf_set_lines(0, 0, -1, false, snippet)
    end,
    group = group,
})

-- On save, rename the module header to the filename
vim.api.nvim_create_autocmd({ "BufWrite" }, {
    pattern = { "*.tla" },
    callback = fix_module_string,
    group = group,
})