diffunitsyntax

Highlight word or character based diff units in diff format

This plugin finds and highlights word or character based changed/added/deleted diff units in a diff format, to make it possible to see the actual differences within a line. This plugin not only works as an additional vim syntax for diff format but also applies the intra-line diff unit highlighting on some popular git-related plugins.

When a file name extension is .diff or the syntax option is set to diff, a diff file in unified format will be shown like this:

This plugin does:

• identify either of unified, context, or normal "ed" style diff format, which can be provided by some program like diff and git diff commands
• find a pair of corresponding changed lines to be compared in a buffer
• realign them to most similar lines if linematch is set in the diffopt option
• split each line to a list of diff units, based on the DiffUnit buffer-local or global variable
• compare them and find the changed/added/deleted units, using a builtin diff() function or a plugin specific function along with the diffopt option
• highlight those diff units according to syntax, text property, or extended mark mechanism applied on the buffer, using single or several background-colored highlight groups, based on the DiffColors buffer-local or global variable

In addition to those standard diff formats, this plugin identifies a file including git conflict markers and diff indicators (-/+ and </>), and then shows the diff units.

git conflict markers

diff indicators

Diff unit highlighting on plugins

In some popular git-related plugins, to show git diff output and to preview a diff hunk in normal, preview, and popup/floating windows, another highlighting mechanism such as text property or extended mark is used instead of diff syntax. This plugin applies the intra-line diff unit highlighting and show actual differences on them, based on the DiffUnitSyntax buffer-local or global variable, on the following plugins (you are welcome to introduce more plugins to cover!):

In normal window:

vim-fugitive >

neogit >

vim-gin >

In preview and popup/floating windows:

gtsigns.nvim >

vim-gitgutter >

vim-signify >

Options

• b:DiffUnit, g:DiffUnit: A type of diff unit

  Value	Description
  'Char'	any single character
  'Word1'	\w\+ word and any \W single character (default)
  'Word2'	non-space and space words
  'Word3'	\< or \> character class boundaries (set by iskeyword option)
  'word'	see word
  'WORD'	see WORD

• b:DiffColors, g:DiffColors: Highlight group for changed units (hl-DiffAdd for added units)

  Value	Description
  0	hl-DiffChange
  1	hl-DiffChange + several highlight groups (default)

• b:DiffUnitSyntax, g:DiffUnitSyntax : Disable this plugin or apply diff unit highlighting

  Value	Description
  0	disable
  1	enable in normal window (default)
  2	enable in normal, preview, and popup/floating windows