Delete/change/yank around indentation scope

[drowning-cat]

mini-indent.mp4

Note

The idea isn’t mine, see Remove outer indentation with mini.indentscope.

Related:

• Delete/change/yank around indentation scope neovim/neovim#34221

Even though I wrote the same keymap multiple times, I’m still not sure if operator mode is the right fit for this. Any feedback would be appreciated.

Version 1

vim.keymap.set("o", "S", function()
  if not vim.list_contains({ "d", "c", "y", "g@" }, vim.v.operator) then
    return
  end

  local scope = MiniIndentscope.get_scope(nil, math.huge)
  for _ = 2, vim.v.count1 do
    scope = MiniIndentscope.get_scope(scope.border.top, math.huge)
  end

  if scope.border.indent < 0 then
    return
  end

  local change = function(from, to, with)
    vim.api.nvim_buf_set_lines(0, from - 1, to, false, with)
  end

  local dedent = function(from, to)
    local count = scope.body.indent - scope.border.indent
    local lines = vim.api.nvim_buf_get_lines(0, from - 1, to, false)
    for i, ln in ipairs(lines) do
      local indent
      indent = vim.fn.indent(from - 1 + i)
      indent = math.max(0, indent - count)
      lines[i] = vim.text.indent(indent, ln, { expandtab = 1 })
    end
    vim.api.nvim_buf_set_lines(0, from - 1, to, false, lines)
  end

  local select = function(from, to)
    vim.api.nvim_win_set_cursor(0, { from, 0 })
    vim.cmd("norm! V")
    vim.api.nvim_win_set_cursor(0, { to, 0 })
  end

  local border, body = scope.border, scope.body
  local inner_lines = vim.api.nvim_buf_get_lines(0, body.top - 1, body.bottom, false)

  if vim.list_contains({ "y", "d", "c" }, vim.v.operator) then
    local copy = {}
    vim.list_extend(copy, vim.api.nvim_buf_get_lines(0, border.top - 1, body.top - 1, false))
    vim.list_extend(copy, vim.api.nvim_buf_get_lines(0, body.bottom, border.bottom, false))
    -- NOTE: `setreg` doesn't work inside `vim.keymap.set("o")`
    vim.schedule(function()
      vim.fn.setreg(vim.v.register, table.concat(copy, "\n"), "l")
    end)
  end

  if vim.v.operator == "y" then
    return
  end

  if vim.v.operator == "d" then
    change(border.top, border.bottom, inner_lines)
    dedent(border.top, border.top + #inner_lines - 1)
    -- HACK: defer cursor to avoid visual selection
    vim.schedule(function()
      MiniIndentscope.move_cursor("top", true, scope)
    end)
  end

  if vim.v.operator == "c" then
    table.insert(inner_lines, 1, "")
    change(border.top, border.bottom, inner_lines)
    dedent(border.top + 1, border.top + #inner_lines - 1)
    select(border.top, body.top - 1)
  end

  if vim.v.operator == "g@" then
    require("vim._comment").toggle_lines(border.top, body.top - 1)
    require("vim._comment").toggle_lines(body.bottom + 1, border.bottom)
  end
end, { desc = "Border scope operator" })

Version 2. Suggested fixes

vim.keymap.set("o", "S", function()
  if not vim.list_contains({ "d", "c", "y", "g@" }, vim.v.operator) then
    return
  end
  if vim.v.operator == 'g@' and not vim.o.operatorfunc:find("vim._comment") then
    return
  end

  local scope = MiniIndentscope.get_scope(nil, math.huge)
  for _ = 2, vim.v.count1 do
    scope = MiniIndentscope.get_scope(scope.border.top, math.huge)
  end
  if scope.border.indent < 0 then
    return
  end

  local change = function(from, to, with)
    vim.api.nvim_buf_set_lines(0, from - 1, to, false, with)
  end
  local dedent = function(from, to)
    vim.cmd(string.format('silent %s,%s <', from, to))
  end
  local cursor = vim.api.nvim_win_get_cursor(0)
  local select = function(from, to)
    if from == false then
      vim.api.nvim_win_set_cursor(0, cursor)
      return
    end
    vim.api.nvim_win_set_cursor(0, { from, 0 })
    vim.cmd [[norm! V]]
    vim.api.nvim_win_set_cursor(0, { to, 0 })
  end

  local border, body = scope.border, scope.body
  local inner_lines = vim.api.nvim_buf_get_lines(0, body.top - 1, body.bottom, false)

  if vim.v.operator == "g@" then
    require("vim._comment").toggle_lines(border.top, body.top - 1)
    require("vim._comment").toggle_lines(body.bottom + 1, border.bottom)
    return
  end

  if vim.list_contains({ "y", "d", "c" }, vim.v.operator) then
    local copy = {}
    vim.list_extend(copy, vim.api.nvim_buf_get_lines(0, border.top - 1, body.top - 1, false))
    vim.list_extend(copy, vim.api.nvim_buf_get_lines(0, body.bottom, border.bottom, false))
    -- NOTE: `setreg` doesn't work inside `vim.keymap.set("o")`
    vim.schedule(function()
      vim.fn.setreg(vim.v.register, table.concat(copy, "\n"), "l")
    end)
  end
  if vim.v.operator == "y" then
    return
  end

  if vim.v.operator == "d" then
    change(border.top, border.bottom, inner_lines)
    dedent(border.top, border.top + #inner_lines - 1)
    select(false)
    -- HACK: defer cursor to avoid visual selection
    vim.schedule(function()
      MiniIndentscope.move_cursor("top", true, scope)
    end)
  end

  if vim.v.operator == "c" then
    table.insert(inner_lines, 1, "")
    change(border.top, border.bottom, inner_lines)
    dedent(border.top + 1, border.top + #inner_lines - 1)
    select(border.top, body.top - 1)
  end
end, { desc = "Border scope textobject" })

[echasnovski]

Thanks for sharing. There are couple of issues I noticed:

• The dedent function will force replace tab indentation into spaces. This is usually a big issue. An alternative is to manually compute target indent space based on the actual leading whitespace. Or use :< command (as done in 'mini.surround').
• The vim.v.operator == "g@" check is true for any custom operator, not only gc. One way to hard-code the action only for specific operator is to check 'operatorfunc', but that might be brittle.
• The "o" (Operator-pending) mode mappings do not represent operators. They are motions (acts from cursor to some place; usually also work in Normal and Visual mode) or textobjects (computes and selects a region regardless of the cursor position). So the better description is "Border scope textobjet".

[drowning-cat]

Thank you for the feedback, I always appreciate it.

I’ve used < to dedent before, and it works well, but it moves the cursor (which isn’t a big deal since it can be restored) and also changes the cursor position in a way that prevents u from bringing me back to the previous spot after undo. Your shift function works in a different way.

Also, thanks for pointing out 2 and 3.

Your codebase is always a great source of inspiration and good practices 😆