Emacs extensions

This is a small, independent collection of Emacs minor modes. Most of these require a recent version of GNU emacs (i.e., version 25+).

Quoting

quote-per-event-mode is a minor mode that provides a single function, "quote-per-event", for on-demand quoting and unquoting of regions, things-at-point and points.

quote-per-event-mode is not an "electric" mode, i.e., it's not intended for rebinding self-insert characters nor for modifying "self-insert-command". Instead of typing, e.g., (, to insert a pair of balanced parentheses, the default binding is CTRL + (.

Alternative "balanced-pair" minor modes worth exploring:

• Electric Pair
• Par Edit
• SmartParens
• Auto Pairs

Jumping between edits

mark-navigation-mode is a minor mode that provides bindings for forward and backward traversal of local and global mark rings. In particular, it's useful for returning to the location of a previous edit or jumping between edits.

Unicode keymap extensions

unicode-keymap-extensions-mode is a minor mode that provides extended Unicode (CTRL-X 8 keymap) bindings.

Align numbers

align-numbers is an Emacs function to align a table of numbers on their radix or decimal point. It's built around the native Emacs function align-regexp.

Insert magic numbers

executable-set-magic-mode is a minor mode that makes a script executable and sets its magic number (or shebang), if any, based on the current major mode.

Installing Emacs extensions

Note that to use these extensions, as is, requires at least Emacs 25 (the current version as of this writing). To use them with earlier versions of Emacs, in each source file comment out the "*-local-mode" minor mode declaration.

To install quote-per-event-mode

Place the file quote-per-event.el in Emacs load path, and add to Emacs init file ~/.emacs or ~/.emacs.d/init.el:

(require 'quote-per-event)

To enable it globally, add:

(quote-per-event-mode)

To enable it locally per major mode - .e.g, only in elisp-mode - use instead:

(add-hook 'elisp-mode-hook
  #'quote-per-event-local-mode)

To enable it globally with some exceptions - e.g., everywhere except elisp-mode - use:

(quote-per-event-mode)
(add-hook 'elisp-mode-hook
  (lambda ()
    (quote-per-event-local-mode -1)))

The default key bindings are as follows:

Binding	Open-char	Close-char
CTRL + '	'	'
CTRL + `	`	'
CTRL + "	"	"
CTRL + :	:	:
CTRL + (	(	)
CTRL + <	<	>
CTRL + {	{	}
CTRL + $	$	$
CTRL + %	%	%
CTRL + *	*	*
CTRL + |	|	|
META + [	[	]
META + _	_	_
CTRL + .	.	.
CTRL + ,	,	,
META + "	«	»
META + *	/	/
CTRL + META + @	@	@
CTRL + META + ?	?	?
CTRL + META + `	`	`
CTRL + META + \	\	\
CTRL + META + '	‘	’
CTRL + META + "	“	”

NB: the last two are typographic (i.e., “curved”) quotes.

To insert, for instance, a C-style comment /* */, press META + * followed by CTRL + *.

Inserting a TeX display environment \[ \] is similar. I use the key sequence CTRL + META + \, select one character forward CTRL + SHIFT + F and then META + [.

To install unicode-keymap-extensions-mode

Place the file unicode-keymap-extensions.el in Emacs load path, and add to Emacs init file ~/.emacs or ~/.emacs.d/init.el:

(require 'unicode-keymap-extensions)

To enable it globally, add:

(unicode-keymap-extensions-mode)

To enable it locally per major mode - .e.g, only in elisp-mode - use instead:

(add-hook 'elisp-mode-hook
  #'unicode-keymap-extensions-local-mode)

To enable it globally with some exceptions - e.g., everywhere except elisp-mode - use:

(unicode-keymap-extensions-mode)
(add-hook 'elisp-mode-hook
  (lambda ()
    (unicode-keymap-extensions-local-mode -1)))

Now, typing CTRL + x 8 g a inserts the greek character α (alpha), CTRL + x 8 r f inserts the Russian character ф (ef), etc.

To install mark-navigation-mode

Place the file mark-navigation.el in Emacs load path, and add to Emacs init file ~/.emacs or ~/.emacs.d/init.el:

(require 'mark-navigation)

To enable it globally, add:

(mark-navigation-mode)

To enable it locally per major mode - .e.g, only in elisp-mode - use instead:

(add-hook 'elisp-mode-hook
  #'mark-navigation-local-mode)

To enable it globally with some exceptions - e.g., everywhere except elisp-mode - use:

(mark-navigation-mode)
(add-hook 'elisp-mode-hook
  (lambda ()
    (mark-navigation-local-mode -1)))

The default mappings are META + P and META + N for previous and next, respectively. The mode is disabled in the mini-buffer.

To install align-numbers

Place the file align-numbers.el in Emacs load path, and add to Emacs init file ~/.emacs or ~/.emacs.d/init.el:

(require 'align-numbers)

Since this is just an Emacs function, invoke it on a region with META-x align-numbers.

To install executable-set-magic-mode

Place the file executable-set-magic.el in Emacs load path, and add to Emacs init file ~/.emacs or ~/.emacs.d/init.el:

(require 'executable-set-magic)
(executable-set-magic-mode)

By default, this inserts magic numbers of the form #!/path/to/interpreter.

To get magic numbers of the form #!/usr/bin/env interpreter, add to Emacs init file:

(setq executable-prefix-env t)

The variable executable-prefix-env is defined since Emacs version 26.1. To allow executable-set-magic-mode to update an existing magic number upon opening a file, apply the patch in the contrib directory contrib/lisp_progmodes_executable.el.diff.

Files in project directories are excluded from processing by default. To apply executable-set-magic-mode to project files as well, add to Emacs init file:

(setq executable-exclude-project-files nil)