highlight-leading-spaces

Overview

This minor-mode highlights leading spaces with a face and replaces them with a special character so they can easily be counted (this can be disabled).

The whitespace.el package that is built-in to Emacs can be used to accomplish the same effect, but for all spaces, including non-leading spaces between words. This minor-mode only highlights leading spaces that are part of the indentation.

The face to highlight leading spaces with can be customised by changing the highlight-leading-spaces face. The character to replace leading spaces with can be customised by changing highlight-leading-spaces-char. If you do not wish to them to be replaced with a special character, set it to a space.

This minor-mode is quite efficient because it doesn't use overlays but text properties for the leading spaces. Furthermore, the highlights are correctly and efficiently kept up-to-date by plugging in to font-lock, not by adding various hooks.

Installation

MELPA

1. Install the highlight-leading-spaces package.

2. Use the highlight-leading-spaces-mode hook to enable this minor-mode:

   (add-hook 'prog-mode-hook 'highlight-leading-spaces-mode)

use-package

Users of use-package can add the following lines to their config:

(use-package highlight-leading-spaces
  :ensure t
  :defer t
  :init (add-hook 'prog-mode-hook 'highlight-leading-spaces-mode))

Manual

Download this package and add the following lines to your config.

(add-to-list 'load-path "/path/to/highlight-leading-spaces")
(require 'highlight-leading-spaces)
(add-hook 'prog-mode-hook 'highlight-leading-spaces-mode)

Licence

Distributed under the GNU General Public License.