fold-preview.nvim

This plugin allows you to preview close folds, without opening them.

https://user-images.githubusercontent.com/13056013/148261501-56677c8f-24a7-4c45-b008-8c1863bf06e8.mp4

Table of contents

• Instalation and setup
• Configuration
  • default_keybindings
  • border
• Keybindings
  • Custom keybindings
    • Main functions
    • Mapping functions
• Highlight

Instalation and setup

To install and setup with packer use this snippet:

use { 'anuvyklack/fold-preview.nvim',
   requires = 'anuvyklack/keymap-amend.nvim',
   config = function()
      require('fold-preview').setup()
   end
}

Configuration

To configure the plugin, you need to pass options into setup() function inside table. Below are available options.

default_keybindings

boolean (default: true)

Set to false to disable default keybindings.

border

"none" | "single" | "double" | "rounded" | "solid" | "shadow" | string[]
default: { ' ', '', ' ', ' ', ' ', ' ', ' ', ' ' }

See: :help nvim_open_win()

Keybindings

I personally don't want to learn a new key combination to preview folds. So I tried to create something that would feel natural.

By default h and l keys are used. On first press of h key, when cursor is on a closed fold, the preview will be shown. On second press the preview will be closed and fold will be opened. When preview is opened, the l key will close it and open fold. In all other cases theese keys will work as usual.

A preview window also will be closed on any cursor move, changing mode, or buffer leaving.

Custom keybindings

Main functions

There three main functions in the require('fold-preview') module:

• show_preview()
  Open preview window if cursor is on a closed fold.

• close_preview() | nil
  Close preview if opened, other way this key will be nil, so you need to check availability manually.

• toggle_preview()
  Close preview if opened, else if cursor is on a closed fold — show preview.

Mapping functions

Also, there are several special functions which allow you to create an interface similar to the default one. They are contains in mapping table:

require('fold-preview').mapping

These functions meant to be used with keymap-amend.nvim plugin. Read its documentation to find out what is original in next functions signatures.

• show_close_preview_open_fold(original)
  Show preview when cursor is inside closed fold. If preview window is already opened, close it and open fold. If no closed fold under the cursor, execute original mapping.

• close_preview_open_fold(original)
  If cursor is on closed fold — open it. If preview is opened, it will be closed. Otherway execute original mapping.

• close_preview(original)
  Close preview (if opened) and execute original mapping.

• close_preview_without_defer(original)
  Close preview immediately: without very small defer which is added in all other functions to avoid annoying screen flickering during fold opening, and execute original mapping. This function is for when you want to close fold preview without opening fold.

Here are default keybindings:

local keymap = vim.keymap
keymap.amend = require('keymap-amend')
local map = require('fold-preview').mapping

keymap.amend('n', 'h',  map.show_close_preview_open_fold)
keymap.amend('n', 'l',  map.close_preview_open_fold)
keymap.amend('n', 'zo', map.close_preview)
keymap.amend('n', 'zO', map.close_preview)
keymap.amend('n', 'zc', map.close_preview_without_defer)
keymap.amend('n', 'zR', map.close_preview)
keymap.amend('n', 'zM', map.close_preview_without_defer)

Highlight

This plugin defines two highlight groups to customize the preview window:

• FoldPreview — linked to NormalFloat by default;
• FoldPreviewBorder — linked to FloatBorder by default.