how to custom textobject?

[lost22git]

Contributing guidelines

• I have read CODE_OF_CONDUCT.md

Module(s)

mini.ai

Question

how to add custom textobject for the below text block?

=beigin Title
some code...
some code...
=end Title

[echasnovski]

I think the most straightforward and robust way here would be to use function that returns array of regions. So something like this:

local custom_block = function(ai_type, _, _)
  local lines = vim.api.nvim_buf_get_lines(0, 0, -1, false)
  local title_start_lines, res = {}, {}

  local process_line = function(i, l)
    -- If line is for "begin", document it and move on until its "end" part
    local start_title = l:match('^=begin (.*)$')
    if start_title ~= nil then
      title_start_lines[start_title] = i
      return
    end

    -- Use only "end" lines that have same title as some previous "begin"
    local end_title = l:match('^=end (.*)$')
    if end_title == nil or title_start_lines[end_title] == nil then return end

    -- Ignore "begin" and "end" lines for `i` textobject
    local from_line = title_start_lines[end_title] + (ai_type == 'i' and 1 or 0)
    local to_line = i - (ai_type == 'i' and 1 or 0)
    title_start_lines[end_title] = nil

    if from_line >= to_line then return end
    local to_col = ai_type == 'i' and vim.fn.getline(to_line):len() or l:len()
    local from, to = { line = from_line, col = 1 }, { line = to_line, col = to_col }
    table.insert(res, { from = from, to = to, vis_mode = 'V' })
  end

  for i, l in ipairs(lines) do
    process_line(i, l)
  end

  return res
end

require('mini.ai').setup({ custom_textobjects = { x = custom_block } })