Vim Free Drag

This plugin enables the movement of rectangular blocks of text, selected using Vim's visual block mode. It was inspired by running into this issue with a similar plugin vim-schlepp, which was an adaptation of DragVisuals.vim.

Movement Model

When a block of text moves in a particular direction, there is quite likely to be a pre-existing row or column of text that is now covered by the text being moved. This plugin moves text by displacement: Pre-existing text in the direction of movement is used to fill the space that is left behind by the moved text. Where there is no pre-existing text and the movement direction is Right or Down, the plugin assumes whitespace. For example, consider the following block of text. Suppose we selection the rectangular block 4710..

1234
5478
9102

Moving this block Up will move the line above it down to fill the gaps in the row that was left behind on the bottom.

1474
5108
9232

Moving this block Down creates a new line and then moves the whitespace from the newline into the row that was left behind on the top.

1234
5  8
9472
 10

Moving this block Left:

1234
4758
1092

Moving this block Right:

1234
5847
9210

Installation

Simply clone this plugin into the plugin directory that is read by Vim8.

pushd  ~/.vim/pack/plugins/start
git clone https://github.com/hq6/VimFreeDrag.git

To actually use it, create mappings in your ~/.vimrc for each direction of dragging.

vmap <unique> K  <Plug>FreeDragUp
vmap <unique> J  <Plug>FreeDragDown
vmap <unique> H  <Plug>FreeDragLeft
vmap <unique> L  <Plug>FreeDragRight

Please create issues if you find scenarios where it does not work as expected that are not described in the limitations section.

Background

While creating ASCII art for architecture diagrams, I realized that I needed to be able to drag entire blocks around relatively independently of surrounding text. I remembered listening to a talk by Damian Conway where he discussed a plugin called DragVisuals.vim. Searching around the web found various versions that were rather buggy. Eventually, I found vim-schlepp, which seemed to be the spiritual sucessor to DragVisuals.vim. Unfortunately, that plugin behaved one way when moving text up and down, and a different way when moving text left and right. This clashed with my mental model for how dragging text should work; hence the creation of this plugin.

Limitations

• Works only with in Visual Block mode. It will detect and reject other visual modes.
• This plugin has undefined behavior when the selection is non-rectangular; this can happen when using the $ command in visual block mode.