mini.move: less intrusive blockwise movement

[matu3ba]

Contributing guidelines

• I have read CONTRIBUTING.md
• I have read CODE_OF_CONDUCT.md

Module(s)

mini.move

Description

Use case
Drawing block selections up and down breaks right-wards indentation, which can make virtual edits for adjusting graphics unnecessary painful. I hope below drawings show the problem. Any kind of ideas would be appreciated.

Problem Description

got

                           ┌──────────────┐
                           │              │
                           │              │
          ┌────────────┐   │              │
          │    upsii   │   │              │
          │     123    │   │              │
          │            │   └──────────────┘
          │            │
          │            │
          └────────────┘

want without redundant steps
1 box selection copy
2 selection replace whitespace
3 selection wanted position and paste

                           ┌──────────────┐
                           │              │
                           │              │
          ┌────────────┐   │              │
          │            │   │              │
          │            │   │              │
          │    upsii   │   └──────────────┘
          │     123    │
          │            │
          └────────────┘

current behavior:
1 line selection movements dont work for multiple lines
2 minimove.move_selection up/down breaks right-hand intendation

                           ┌──────────────┐
                           │              │
                           │              │
          ┌────────────┐   │              │
          │       │   │              │
          │       │   │              │
          │    upsii        │   └──────────────┘
          │     123         │
          │            │
          └────────────┘

It would be nice, if move_selection would have another mode
so that a move is an actual swap of text elements freely
into the buffer positions, so moving 1 upwards does

                           ┌──────────────┐
                           │              │
                           │              │
          ┌────upsii───┐   │              │
          │     123    │   │              │
          │    ─────   │   │              │
          │            │   └──────────────┘
          │            │
          │            │
          └────────────┘

and moving 1 more upwards does

                           ┌──────────────┐
                           │              │
               upsii       │              │
          ┌──── 123 ───┐   │              │
          │    ─────   │   │              │
          │            │   │              │
          │            │   └──────────────┘
          │            │
          │            │
          └────────────┘

until

               upsii       ┌──────────────┐
                123        │              │
                           │              │
          ┌────────────┐   │              │
          │            │   │              │
          │            │   │              │
          │            │   └──────────────┘
          │            │
          │            │
          └────────────┘

with the internal position of the collision range be kept.
To me it looks like you have implemented collision detection,
but nothing to keep track of correct fixups after nothig collides.
For example, left and right movements have the same behavior:

                           ┌──────────────┐
                           │              │
                           │              │
          ┌────────────┐   │              │
  upsii        │       │   │              │
   123         │       │   │              │
          │            │   └──────────────┘
          │            │
          │            │
          └────────────┘

local selmove_hint = [[
 Arrow^^^^^^
 ^ ^ _k_ ^ ^
 _h_ ^ ^ _l_
 ^ ^ _j_ ^ ^                      _<C-c>_
]]

local ok_minimove, minimove = pcall(require, 'mini.move')
assert(ok_minimove)
if ok_minimove == true then
  local opts = {
    mappings = {
      left = '',
      right = '',
      down = '',
      up = '',
      line_left = '',
      line_right = '',
      line_down = '',
      line_up = '',
    },
  }
  minimove.setup(opts)
  -- setup here prevents needless global vars for opts required by `move_selection()/moveline()`
  M.minimove_box_hydra = Hydra {
    name = 'Move Box Selection',
    hint = selmove_hint,
    config = {
      color = 'pink',
      invoke_on_body = true,
    },
    mode = 'v',
    body = '<leader>vb',
    heads = {
      {
        'h',
        function() minimove.move_selection('left', opts) end,
      },
      {
        'j',
        function() minimove.move_selection('down', opts) end,
      },
      {
        'k',
        function() minimove.move_selection('up', opts) end,
      },
      {
        'l',
        function() minimove.move_selection('right', opts) end,
      },
      { '<C-c>', nil, { exit = true } },
    },
  }
  M.minimove_line_hydra = Hydra {
    name = 'Move Line Selection',
    hint = selmove_hint,
    config = {
      color = 'pink',
      invoke_on_body = true,
    },
    mode = 'n',
    body = '<leader>vl',
    heads = {
      {
        'h',
        function() minimove.move_line('left', opts) end,
      },
      {
        'j',
        function() minimove.move_line('down', opts) end,
      },
      {
        'k',
        function() minimove.move_line('up', opts) end,
      },
      {
        'l',
        function() minimove.move_line('right', opts) end,
      },
      { '<C-c>', nil, { exit = true } },
    },
  }
end

[echasnovski]

Thanks for the suggestion!

I can reproduce. At first glance, it is indeed not a very good behavior. However, blockwise movement is kind of lesser tier of support for 'mini.move' because of how complicated it is to implement.

I'll look more into why this happens.