char-font-lock - Highlight bad whitespace and out-of-place characters

Author: Anders Lindgren
Version: 0.0.2
URL: https://github.com/Lindydancer/char-font-lock

Char Font Lock is an Emacs package that highlight bad whitespace and out-of-place characters.

Char Font Lock is implemented as two minor modes: char-font-lock-mode, which can be applied to an individual buffer, and char-font-lock-global-mode which automatically enables the mode in all existing and future buffers.

What is highlighted

Currently, the following are highlighted:

• Correct tab characters are highlighted using a neutral color, to indicate that they are there
• Incorrect tabs, i.e. tabs not first on the line or any tab in case indent-tabs-mode isn't active
• Empty lines at the end of the buffer
• The last line, if it ends without a newline
• End of line whitespace. (Technically, this is not highlighted using a font-lock keyword, instead the built-in feature show-trailing-whitespace is used.)

Installation

This package is designed to be installed as a "package". Once installed, it is automatically activated.

Customization

The following variables can be modified to fine-tune Char Font Lock:

• char-font-lock-modes -- For major modes that are members of this list, or are derived from members in this list, Char Font Lock Global mode will be enabled. As prog-mode and text-mode initially are members, this mean that Char Font Lock is enabled for most major modes, with the exception of special major modes like help-mode. Some ancient third-party major modes are not derived from the base modes provided by Emacs, in this case you can explicitly add them to this list (alternatively, politely ask their authors to take a step into the modern world).
• char-font-lock-enabled-features-list -- Control which highlight rules should be applied to a major mode. For example, with the default settings, end-of-file whitespace for lisp-interaction-mode (used by the scratch buffer) is not highlighted.

Example

Below is a screenshot of a sample file, demonstrating the effect of this package:

Supported Emacs Versions

This package is primarily for Emacs 24.4. However, with the help of the companion package old-emacs-support it can be used with earlier Emacs versions, at least from Emacs 22.

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Converted from char-font-lock.el by el2markdown.