Is possible to add in lualine the amount of marks that the file have ?

[barcell1]

basic the title

[andreihh]

You can get the list of marks for the current buffer with vim.fn.getmarklist(vim.api.nvim_get_current_buf()). From there, you can discard default / builtin marks and count only how many lowercase letter marks are returned. E.g.:

{
  function()
    local marks = vim.fn.getmarklist(vim.api.nvim_get_curent_buf())
    local marks_count = 0
    for _, mark in ipairs(marks) do
      local mark_symbol = mark.mark:sub(2,2) -- first character is always single-quote
      count = count + ('a' <= mark_symbol and mark_symbol <= 'z' and 1 or 0)
    end
    return marks_count
  end,
  icon = "" -- `nf-fa-bookmark`
}