Emacs Mini Manual (PART 3) - CUSTOMIZING AND EXTENDING EMACS

If you want to change a specific setting, you need to change a variable value. You wonder, there are so many variables to set. How do you know which to which? Luckily, you don't have to manually guess which variable to set. Emacs has a command for setting Emacs internally, with a nice organization of settings, rather than randomly set a variable that you randomly found. M-x customize to open a window for customizing Emacs:

You will see various categories for customizing Emacs. These categories are called Customization Groups in Emacs. Let's try setting something in Emacs:

• Go to Editing -> Editing Basics -> move point to "Global

Mark ring Max: ".

• Change the value to 5000.
• Move point on State button. Press RET.
• A menu appears with the following choice:

0 = Set for current Sesssion This option is for trying out a new setting. If you close Emacs, the old setting is restored.

1 = Save for Future Sesssions This option saves the new value permanently, so the next time you start Emacs, it uses your saved setting. The new value is saved at ~/.emacs.d/init.el like this:

(custom-set-variables
 ;; custom-set-variables was added by Custom.
 ;; If you edit it by hand, you could mess it up, so be careful.
 ;; Your init file should contain only one such instance.
 ;; If there is more than one, they won't work right.
 '(global-mark-ring-max 5000))

2 = Undo Edits: Undo to the previous value of a particular setting, if you haven't set.

3 = Revert This Sesssion's Customization: This restores the value of the variable to the last saved value, and updates the text accordingly.

4 = Erase Customization: Reset to standard value and delete set value in ~/emacs.d/init.el.

7 = Add Comment: Sometimes you have something to say about your customization. Write it using this option.

: = Show Saved Lisp Expression: Show the actual variable representation. If you open the menu again, the option : = Show Saved Lisp Expression is changed to Show current value that switches back to the nicer representation.

Another way to change a setting is using C-h v, which runs describe-variable that list all the available variables in your Emacs and allow you to select one. You can also access the parent group of a group or a variable.

Aside from the general customize command, Emacs has many more customization command: customize-group, customize-face… That organize customization groups in different ways. However, in the scope of this guide, we only use customize for customize Emacs generally and customize-group to select a specific package for customizing, and also find out which parent group the package belongs to, after you finished installing from the package manager.

The above approach uses GUI, which makes Emacs look familiar to normal users from other editors: using GUI to change the editors. However, it has disadvantages: Monolithic. Although the settings are nicely organized into groups, its underlying representation is not. After you set and save something in whatever group, Emacs always add your setting to the function custom-set-variables like this:

(custom-set-variables
 ;; custom-set-variables was added by Custom.
 ;; If you edit it by hand, you could mess it up, so be careful.
 ;; Your init file should contain only one such instance.
 ;; If there is more than one, they won't work right.
 '(global-mark-ring-max 5000 nil nil "test"))

As you can read it the comment, custom-set-variables is expected to be unique in your init file. If you have more, things go wrong. So, by design, you cannot split the settings into logical groups of your choice.

For that reason, setq is the preferred method. But, you can use the GUI with nice and logical grouping to guide you to the settings you want to change. The grouping is nice, and for consistency, we should organize our module structure based on the grouping in M-x customize:

• setup-editing.el for Editing group.
• setup-convenience.el for Convenience group.
• setup-files.el for Files group.
• setup-text.el for Text group.
• setup-data.el for Data group.
• setup-external.el for External group.
• setup-communication.el for Communication group.
• setup-programming.el for Programming group.
• setup-applications.el for Application group.
• setup-development.el for Development group.
• setup-environment.el for Environment group.
• setup-faces.el for Faces group.
• setup-help.el for Help group.
• setup-multimedia.el for Multimedia group.
• setup-local.el for Local group.

Please note that even though you may see some packages are inside a group in customize GUI, I still put in another group since I feel such packages are more appropriate. So, if you see packages in my setup are in different groups, don't be surprise. But it's just my personal opinion. You can move it where you want.

Exercise:

• Create a directory: ~/.emacs.d/custom/
• Create the above setup-*.el files under it.
• Load the files above using mapc:

(mapc 'load (directory-files "~/.emacs.d/custom" t ".*\.el"))

You already installed the package rebox2 in How to use Emacs package manager section. When you mark a region and M-q, you can create the above comment box. There are many styles, you can cycle by pressing M-q repeatedly.

Now, everything is prepared. We can really dive into customizing and extending Emacs with 3rd party packages and various code snippets that solve many little problems. In later sections, each is dedicated to a category. But, please note that I only provide the customizations that I found useful, not templates that you have to follow rigidly. You can consider my customizations as an example for your own customizations. You can use it either way:

• Copy the sample configurations into your files and look back later or just don't care.
• Really control the customization process and make the customizations actually yours, by reading the customization code and understand what it does.

Author:

Sergey Pashinin, sergey@pashinin.com

Based on the original workgroups, created by tlh, thunkout@gmail.com.

Homepage: Github

Features:

Workgroups is a session manager for Emacs.

• It saves all your opened buffers, their location and sizes on disk to restore later.
• You can create several workspaces.

You can also restore such buffers as: org-agenda, shell, magit-status, help.

Installation:

M-x list-packages and select workgroups2 package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; PACKAGE: workgroups2               ;;
;;                                    ;;
;; GROUP: Convenience -> Workgroups   ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(require 'workgroups2)
;; Change some settings
(workgroups-mode 1)

Remember to put the code at the bottom of init.el, after everything is properly initialized.

Usage:

Most commands are bound to both <prefix> <key> and <prefix> C-<key>.

By default prefix is: "C-c z" (To change it - see settings below)

<prefix> <key> <prefix> c - create workgroup <prefix> A - rename workgroup <prefix> k - kill workgroup <prefix> v - switch to workgroup <prefix> C-s - save session <prefix> C-f - load session <prefix> 0..9 - switch to workgroup at index 0..9

Do you remember how to use registers to store window configurations? Registers are good, but it does not allow you to name window configurations. It would be trouble when the number of window configurations getting large. You will have to tediously remember which register stores which configuration.

With workgroups2, each window configuration is a workgroup, and you can create as many workgroups and named it with <prefix> c; later, you can switch back by <prefix> v. Because you can name your window configurations, you don't have the burden to remember which to which in registers. You can also save your window configurations to continue using them in later Emacs sessions.

Sometimes, we want to adjust or improve the behaviours of some commands in certain contexts. Consider this situation: C-a, which runs move-beginning-of-line, always move to the beginning of line. However, sometimes we don't always to move to the beginning of line, but move to the first non-whitespace character of that line.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Customized functions                ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(defun prelude-move-beginning-of-line (arg)
  "Move point back to indentation of beginning of line.

Move point to the first non-whitespace character on this line.
If point is already there, move to the beginning of the line.
Effectively toggle between the first non-whitespace character and
the beginning of the line.

If ARG is not nil or 1, move forward ARG - 1 lines first. If
point reaches the beginning or end of the buffer, stop there."
  (interactive "^p")
  (setq arg (or arg 1))

  ;; Move lines first
  (when (/= arg 1)
    (let ((line-move-visual nil))
      (forward-line (1- arg))))

  (let ((orig-point (point)))
    (back-to-indentation)
    (when (= orig-point (point))
      (move-beginning-of-line 1))))

(global-set-key (kbd "C-a") 'prelude-move-beginning-of-line)

(defadvice kill-ring-save (before slick-copy activate compile)
  "When called interactively with no active region, copy a single
line instead."
  (interactive
   (if mark-active (list (region-beginning) (region-end))
     (message "Copied line")
     (list (line-beginning-position)
           (line-beginning-position 2)))))

(defadvice kill-region (before slick-cut activate compile)
  "When called interactively with no active region, kill a single
  line instead."
  (interactive
   (if mark-active (list (region-beginning) (region-end))
     (list (line-beginning-position)
           (line-beginning-position 2)))))

;; kill a line, including whitespace characters until next non-whiepsace character
;; of next line
(defadvice kill-line (before check-position activate)
  (if (member major-mode
              '(emacs-lisp-mode scheme-mode lisp-mode
                                c-mode c++-mode objc-mode
                                latex-mode plain-tex-mode))
      (if (and (eolp) (not (bolp)))
          (progn (forward-char 1)
                 (just-one-space 0)
                 (backward-char 1)))))

;; taken from prelude-editor.el
;; automatically indenting yanked text if in programming-modes
(defvar yank-indent-modes
  '(LaTeX-mode TeX-mode)
  "Modes in which to indent regions that are yanked (or yank-popped).
Only modes that don't derive from `prog-mode' should be listed here.")

(defvar yank-indent-blacklisted-modes
  '(python-mode slim-mode haml-mode)
  "Modes for which auto-indenting is suppressed.")

(defvar yank-advised-indent-threshold 1000
  "Threshold (# chars) over which indentation does not automatically occur.")

(defun yank-advised-indent-function (beg end)
  "Do indentation, as long as the region isn't too large."
  (if (<= (- end beg) yank-advised-indent-threshold)
      (indent-region beg end nil)))

(defadvice yank (after yank-indent activate)
  "If current mode is one of 'yank-indent-modes,
indent yanked text (with prefix arg don't indent)."
  (if (and (not (ad-get-arg 0))
           (not (member major-mode yank-indent-blacklisted-modes))
           (or (derived-mode-p 'prog-mode)
               (member major-mode yank-indent-modes)))
      (let ((transient-mark-mode nil))
        (yank-advised-indent-function (region-beginning) (region-end)))))

(defadvice yank-pop (after yank-pop-indent activate)
  "If current mode is one of `yank-indent-modes',
indent yanked text (with prefix arg don't indent)."
  (when (and (not (ad-get-arg 0))
             (not (member major-mode yank-indent-blacklisted-modes))
             (or (derived-mode-p 'prog-mode)
                 (member major-mode yank-indent-modes)))
    (let ((transient-mark-mode nil))
      (yank-advised-indent-function (region-beginning) (region-end)))))

;; prelude-core.el
(defun prelude-duplicate-current-line-or-region (arg)
  "Duplicates the current line or region ARG times.
If there's no region, the current line will be duplicated. However, if
there's a region, all lines that region covers will be duplicated."
  (interactive "p")
  (pcase-let* ((origin (point))
               (`(,beg . ,end) (prelude-get-positions-of-line-or-region))
               (region (buffer-substring-no-properties beg end)))
    (-dotimes arg
      (lambda (n)
        (goto-char end)
        (newline)
        (insert region)
        (setq end (point))))
    (goto-char (+ origin (* (length region) arg) arg))))

;; prelude-core.el
(defun indent-buffer ()
  "Indent the currently visited buffer."
  (interactive)
  (indent-region (point-min) (point-max)))

;; prelude-editing.el
(defcustom prelude-indent-sensitive-modes
  '(coffee-mode python-mode slim-mode haml-mode yaml-mode)
  "Modes for which auto-indenting is suppressed."
  :type 'list)

(defun indent-region-or-buffer ()
  "Indent a region if selected, otherwise the whole buffer."
  (interactive)
  (unless (member major-mode prelude-indent-sensitive-modes)
    (save-excursion
      (if (region-active-p)
          (progn
            (indent-region (region-beginning) (region-end))
            (message "Indented selected region."))
        (progn
          (indent-buffer)
          (message "Indented buffer.")))
      (whitespace-cleanup))))

(global-set-key (kbd "C-c i") 'indent-region-or-buffer)

;; add duplicate line function from Prelude
;; taken from prelude-core.el
(defun prelude-get-positions-of-line-or-region ()
  "Return positions (beg . end) of the current line
or region."
  (let (beg end)
    (if (and mark-active (> (point) (mark)))
        (exchange-point-and-mark))
    (setq beg (line-beginning-position))
    (if mark-active
        (exchange-point-and-mark))
    (setq end (line-end-position))
    (cons beg end)))

(defun kill-default-buffer ()
  "Kill the currently active buffer -- set to C-x k so that users are not asked which buffer they want to kill."
  (interactive)
  (let (kill-buffer-query-functions) (kill-buffer)))

(global-set-key (kbd "C-x k") 'kill-default-buffer)

;; smart openline
(defun prelude-smart-open-line (arg)
  "Insert an empty line after the current line.
Position the cursor at its beginning, according to the current mode.
With a prefix ARG open line above the current line."
  (interactive "P")
  (if arg
      (prelude-smart-open-line-above)
    (progn
      (move-end-of-line nil)
      (newline-and-indent))))

(defun prelude-smart-open-line-above ()
  "Insert an empty line above the current line.
Position the cursor at it's beginning, according to the current mode."
  (interactive)
  (move-beginning-of-line nil)
  (newline-and-indent)
  (forward-line -1)
  (indent-according-to-mode))

(global-set-key (kbd "C-o") 'prelude-smart-open-line)
(global-set-key (kbd "M-o") 'open-line)

The code above is taken from this article: Smarter Navigation to the Beginning of a Line.

(defadvice kill-ring-save (before slick-copy activate compile)
  "When called interactively with no active region, copy a single
line instead."
  (interactive
   (if mark-active (list (region-beginning) (region-end))
     (message "Copied line")
     (list (line-beginning-position)
           (line-beginning-position 2)))))

(defadvice kill-region (before slick-cut activate compile)
  "When called interactively with no active region, kill a single
  line instead."
  (interactive
   (if mark-active (list (region-beginning) (region-end))
     (list (line-beginning-position)
           (line-beginning-position 2)))))

;; kill a line, including whitespace characters until next non-whiepsace character
;; of next line
(defadvice kill-line (before check-position activate)
  (if (member major-mode
              '(emacs-lisp-mode scheme-mode lisp-mode
                                c-mode c++-mode objc-mode
                                latex-mode plain-tex-mode))
      (if (and (eolp) (not (bolp)))
          (progn (forward-char 1)
                 (just-one-space 0)
                 (backward-char 1)))))

Author: ongaeshi, ongaeshi0621@gmail.com

Homepage: Github

Features:

Easy duplicate line or region, with comment out.

• Duplicate current line.
• Duplicate a selection when selection is active.
• Only C-u, replicate, comment out the range.
• Numerical prefix is specified as 'C-u 5': do multiple times repeatedly.

Installation:

(require 'duplicate-thing)
(global-set-key (kbd "M-c") 'duplicate-thing)

Usage: If point is on a line, the command duplicates the current line. If region is active, duplicates region instead.

Author: Keitalo Miyazaki, Keitaro.Miyazaki@gmail.com

Homepage: Emacswiki

Features:

VolatileHighlights highlights changes to the buffer caused by commands such as ‘undo’, ‘yank’/’yank-pop’, etc. The highlight disappears at the next command. The highlighting gives useful visual feedback for what your operation actually changed in the buffer.

Installation:

M-x list-packages and select volatile-highlights package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Package: volatile-highlights          ;;
;;                                       ;;
;; GROUP: Editing -> Volatile Highlights ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(require 'volatile-highlights)
(volatile-highlights-mode t)

Usage:

When you yank (paste) something, the yanked (pasted) region will be highlighted.

Author: Matus Goljer, matus.goljer@gmail.com

Homepage: Github

Features:

Smartparens is minor mode for Emacs that deals with parens pairs and tries to be smart about it. It started as a unification effort to combine functionality of several existing packages in a single, compatible and extensible way to deal with parentheses, delimiters, tags and the like. Some of these packages include autopair, textmate, wrap-region, electric-pair-mode, paredit and others. With the basic features found in other packages it also brings many improvements as well as completely new features. Here's a highlight of some features, for a complete list and detailed documentation look in the manual.

For the complete documentation visit the documentation wiki.

Installation:

M-x list-packages and select smartparens package, then install it. After finish installing, add this code snippet to activate the package:

;; Package: smartparens
(require 'smartparens-config)
(setq sp-base-key-bindings 'paredit)
(setq sp-autoskip-closing-pair 'always)
(setq sp-hybrid-kill-entire-symbol nil)
(sp-use-paredit-bindings)

Usage:

If smartparens sees a opening/closing of pair, either the default supported ones or customized by users, it will complete the pair. You can even highlight a block of text (region) and enter a pair character, smartparens will wraps the region around the pair. smartparens can also highlight pairs, even pairs with escape characters.

Author: Peter Marinov

Homepage: Github

Features:

When you press RET to create a newline and got indented by eletric-indent-mode, you have appropriate whitespace for indenting. But, if you leave the line blank and move to the next line, the whitespace becomes useless. This package helps clean up unused whitespace.

View this Emacswiki page for more details.

Installation:

M-x list-packages and select clean-aindent-mode package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Package: clean-aindent-mode               ;;
;;                                           ;;
;; GROUP: Editing -> Indent -> Clean Aindent ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(require 'clean-aindent-mode)
(add-hook 'prog-mode-hook 'clean-aindent-mode)

Usage:

Automatically cleanup useless whitespaced on moving up/down.

Author: Toby Cubitt, toby-undo-tree@dr-qubit.org

Homepage: www.dr-qubit.org

Features:

undo-tree allows you to visual the whole history of your editing in a tree. It also provides regular undo/redo behaviours in other editors. undo-tree can even provide a diff between two different states. Highly recommended.

Installation:

M-x list-packages and select undo-tree package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Package: undo-tree                  ;;
;;                                     ;;
;; GROUP: Editing -> Undo -> Undo Tree ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(require 'undo-tree)
(global-undo-tree-mode)

Usage:

From now on, your undo (C-/) behaves just like normal editor. To redo, C-_. To open the undo tree, C-x u.

Author: João Távora

Homepage: Github

Features:

YASnippet is a template system for Emacs. It allows you to type an abbreviation and automatically expand it into function templates. Bundled language templates include: C, C++, C#, Perl, Python, Ruby, SQL, LaTeX, HTML, CSS and more. The snippet syntax is inspired from TextMate's syntax, you can even import most TextMate templates to YASnippet.

Installation:

M-x list-packages and select yasnippet package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Package: yasnippet                 ;;
;;                                    ;;
;; GROUP: Editing -> Yasnippet        ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(require 'yasnippet)
(yas-global-mode 1)

Usage:

In major modes where yasnippet has snippets available, typing a certain keyword and TAB insert a predefined snippet. For example, in a C buffer, if you type for and TAB, it expands to:

for (i = 0; i < N; i++) {
    ...point will be here....
}

You can view supported snippets here.

Author:

• Nikolaj Schumacher (original author)
• Dmitry Gutov (current maintainer), dgutov@yandex.ru

Homepage: http://company-mode.github.io/

Features:

Company is a text completion framework for Emacs. The name stands for "complete anything". It uses pluggable back-ends and front-ends to retrieve and display completion candidates.

It comes with several back-ends such as Elisp, Clang, Semantic, Eclim, Ropemacs, Ispell, CMake, BBDB, Yasnippet, dabbrev, etags, gtags, files, keywords and a few others.

The CAPF back-end provides a bridge to the standard completion-at-point-functions facility, and thus works with any major mode that defines a proper completion function.

Installation:

M-x list-packages and select company package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; PACKAGE: company              ;;
;;                               ;;
;; GROUP: Convenience -> Company ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(add-hook 'after-init-hook 'global-company-mode)

Usage:

Completion will start automatically after you type a few letters. Use M-n and M-p to select, <return> to complete or <tab> to complete the common part. Search through the completions with C-s, C-r and C-o. Press M-(digit) to quickly complete with one of the first 10 candidates.

Author: Magnar Sveen

Homepage: Github

Features: expand-region allows you to select text objects incrementally.

Installation:

M-x list-packages and select expand-region package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Package: expand-region                       ;;
;;                                              ;;
;; GROUP: Convenience -> Abbreviation -> Expand ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(require 'expand-region)
(global-set-key (kbd "M-m") 'er/expand-region)

I bind er/expand-regin to M-m, because the functionality is included from the amended beginning-of-line we did above.

Usage:

M-m to continue expand outward.

Author: Steve Purcell

Homepage: Github

Features:

• Group your buffers by their parent vc root directory
• See the VC status of the associated files
• Sort buffers by their VC status

Installation:

M-x list-packages and select ibuffer-vc package, then install it. After finish installing, add this code snippet to activate the package:

(add-hook 'ibuffer-hook
          (lambda ()
            (ibuffer-vc-set-filter-groups-by-vc-root)
            (unless (eq ibuffer-sorting-mode 'alphabetic)
              (ibuffer-do-sort-by-alphabetic))))

(setq ibuffer-formats
      '((mark modified read-only vc-status-mini " "
              (name 18 18 :left :elide)
              " "
              (size 9 -1 :right)
              " "
              (mode 16 16 :left :elide)
              " "
              (vc-status 16 16 :left)
              " "
              filename-and-process)))

Usage:

When you use ibuffer, it will automatically group buffers by version control system.

Author: Bozhidar Batsov, bozhidar@batsov.com

Homepage: Github

Features:

Projectile is a project interaction library for Emacs. Its goal is to provide a nice set of features operating on a project level without introducing external dependencies(when feasible). For instance - finding project files has a portable implementation written in pure Emacs Lisp without the use of GNU find (but for performance sake an indexing mechanism backed by external commands exists as well).

Projectile tries to be practical - portability is great, but if some external tools could speed up some task substantially and the tools are available, Projectile will leverage them.

This library provides easy project management and navigation. The concept of a project is pretty basic - just a folder containing special file. Currently git, mercurial, darcs and bazaar repos are considered projects by default. So are lein, maven, sbt, rebar and bundler projects. If you want to mark a folder manually as a project just create an empty .projectile file in it. Some of Projectile's features:

• jump to a file in project
• jump to a directory in project
• jump to a file in a directory
• jump to a project buffer
• jump to a test in project
• toggle between code and its test
• jump to recently visited files in the project
• switch between projects you have worked on
• kill all project buffers
• replace in project
• multi-occur in project buffers
• grep in project
• regenerate project etags or gtags (requires gtags).
• visit project in dired
• run make in a project with a single key chord

Here's a glimpse of Projectile in action:

Installation:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; PACKAGES: projectile             ;;
;;                                  ;;
;; GROUP: Convenience -> Projectile ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(projectile-global-mode)

Usage:

Please refer to the usage on the homepage.

Author: Ryan C. Thompson, rct+github@thompsonclan.org

Homepage: Github

Features:

Gimme some ido… everywhere!

Does what you were really hoping for when you did (setq ido-everywhere t). Replaces stock emacs completion with ido completion wherever it is possible to do so without breaking things.

Note that ido-ubiquitous is not enabled for org mode or magit mode, because those modes have their own support for ido.

Installation:

M-x list-packages and select ido-ubiquitous package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; PACKAGE: ido-ubiquitous                                   ;;
;;                                                           ;;
;; GROUP: Development -> Extensions -> Ido -> Ido Ubiquitous ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(ido-ubiquitous-mode +1)

Usage:

Once you activated Ido, it is available where you expect to select and narrow down candidates.

Author: Le Wang

Homepage: Github

Features: M-x list-packages and select flx-ido package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; PACKAGE: flx-ido                                          ;;
;;                                                           ;;
;; GROUP: Development -> Extensions -> Ido                   ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; smarter fuzzy matching for ido
(flx-ido-mode +1)
;; disable ido faces to see flx highlights
(setq ido-use-faces nil)

Usage:

flx-ido provides fuzzy completion to select completion candidates. For example, if you want to select a file src/foo/bar.txt, you only need to type in Ido prompt "sfb", short for (s)rc/(f)oo/(b)ar.

Author: Cornelius Mika, cornelius.mika@gmail.com

Homepage: Github

Features:

Smex is a M-x enhancement for Emacs. Built on top of Ido, it provides a convenient interface to your recently and most frequently used commands. And to all the other commands, too.

Installation:

M-x list-packages and select flx-ido package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; PACKAGE: smex                                             ;;
;;                                                           ;;
;; GROUP: Convenience -> Extensions -> Smex                  ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(require 'smex)
(smex-initialize)
(global-set-key (kbd "M-x") 'smex)
(global-set-key (kbd "M-X") 'smex-major-mode-commands)

Usage:

smex is an improved M-x command. After you setup, M-x to run smex and M-X to select only commands in the current major mode.

Author: Drew Adams, drew.adams@oracle.com

Homepage: Emacswiki

Features: Dired+ (library dired+.el), which extends functionalities provided by standard GNU Emacs libraries dired.el, dired-aux.el, and dired-x.el. The standard functions are all available, plus many more.

Installation:

M-x list-packages and select dired+ package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; PACKAGE: dired+                     ;;
;;                                     ;;
;; GROUP: Files -> Dired -> Dired Plus ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(require 'dired+)

Usage:

Please refer to Emacswiki usage. Note that Dired+ has A LOT of features, but you don't have to learn to use all of them at once. Even the extra faces are useful enough.

Features:

Extension of `recentf' package.

• `dired' buffers can be handled.
• Switching to file buffer considers it as most recent file.

Installation:

M-x list-packages and select recentf-ext package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; PACKAGE: recentf-ext    ;;
;;                         ;;
;; GROUP: Files -> Recentf ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(require 'recentf-ext)

Usage:

When you visit a directory, that directory is saved by recentf as well.

Author: Alexey Veretennikov, alexey.veretennikov@gmail.com

Homepage: Github

Features:

Ztree is a project dedicated to implementation of several text-tree applications inside Emacs. It consists of 2 sub-projects: ztree-diff and ztree-dir(the basis of ztree-diff).

• ztree-diff: Perform diff on two directories. Really handy when you want to create a big patch between two directories.

• ztree-dir: a simple tree explorer.

Installation:

M-x list-packages and select ztree package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;
;; PACKAGE: ztree  ;;
;;                 ;;
;; GROUP: No group ;;
;;;;;;;;;;;;;;;;;;;;;
;; since ztree works with files and directories, let's consider it in
;; group Files
(require 'ztree-diff)
(require 'ztree-dir)

Usage:

M-x ztree-diff, then select the left and right directories to compare.

M-x ztree-dir to explorer filesystem:

• Open/close directories with double-click, RET or Space keys.
• To jump to the parent directory, hit the Backspace key.
• To toggle open/closed state of the subtree of the current directory, hit the x key.

Author: Andrey Kotlarski, m00naticus@gmail.com

Homepage: Github

Features:

Emacs minor mode that allows viewing, editing, searching and comparing large files in batches. Batch size can be adjusted on the fly and bounds the memory that is to be used for operations on the file. This way multiple large files (like terabytes or whatever) can be instantly and simultaneously accessed without swapping and degraded performance.

This is development version of the GNU ELPA VLF package. Here’s what it offers in a nutshell:

• regular expression search on whole file (in constant memory determined by current batch size)
• chunk editing (if size has changed, saving is done in constant memory determined by current batch size)
• Occur like indexing
• options to jump to beginning, end or arbitrary file chunk
• ability to jump/insert given number of batches at once
• newly added content is acknowledged if file has changed size meanwhile
• automatic scrolling of batches
• as a minor mode, font locking and functionality of the respective major mode is also present
• by batch Ediff comparison
• can be added as option to automatically open large files
• smooth integration with hexl-mode
• works with TRAMP so accessing network files is fine

GNU Emacs 23 and 24 are supported.

Installation:

M-x list-packages and select ** package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;
;; PACKAGE: vlf        ;;
;;                     ;;
;; GROUP: Files -> Vlf ;;
;;;;;;;;;;;;;;;;;;;;;;;;;
(require 'vlf-integrate)
(setq vlf-application 'dont-ask) ;; automatically use vlf on large file,
                                 ;; when the file exceed large-file-warning-threshold

Usage:

Please refer to Detail Usage section.

Author: Dmitry Gutov, dgutov@yandex.ru

Homepage: Github

Features:

diff-hl-mode highlights uncommitted changes on the left side of the window, allows you to jump between and revert them selectively.

For the usage instructions and the list of commands, see the Commentary section inside the file.

Tested with Git, Mercurial, Bazaar and SVN. May work with other VC backends, too.

The package also contains auxiliary modes:

• diff-hl-dired-mode provides similar functionality in Dired.

  

• diff-hl-margin-mode changes the highlighting function to use the margin instead of the fringe.

  

• diff-hl-amend-mode shifts the reference revision back by one.

Installation:

M-x list-packages and select diff-hl package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; PACKAGE: diff-hl                             ;;
;;                                              ;;
;; GROUP: Programming -> Tools -> Vc -> Diff Hl ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(global-diff-hl-mode)
(add-hook 'dired-mode-hook 'diff-hl-dired-mode)

Usage:

To see diff-hl in action, open a buffer under a version control and type something and save. You will see highlighted changes in the fringe on the left.

It is also similar with diff-hl-dired-mode.

Author:

Original Author: Marius Vollmer marius.vollmer@gmail.com

Maintainer: Jonas Bernoulli, jonas@bernoul.li

Former-Maintainers:

• Nicolas Dudebout, nicolas.dudebout@gatech.edu
• Peter J. Weisberg, pj@irregularexpressions.net
• Phil Jackson, phil@shellarchive.co.uk
• Rémi Vanicat, vanicat@debian.org
• Yann Hodique, yann.hodique@gmail.com

Homepage: http://magit.github.io

Features: Magit is an interface to the version control system Git, implemented as an Emacs extension.

Unlike Emacs' native Version Control package which strives to provide a unified interface to various version control systems, Magit only supports Git and can therefore better take advantage of its native features.

Magit supports GNU Emacs 23.2 or later; 24.1 or later is recommended. Magit supports Git 1.7.2.5 or later; 1.8.2 or later is recommended. The minimal versions are those available in Debian oldstable.

Installation:

M-x list-packages and select magit package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; PACKAGE: magit                       ;;
;;                                      ;;
;; GROUP: Programming -> Tools -> Magit ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(require 'magit)
(set-default 'magit-stage-all-confirm nil)
(add-hook 'magit-mode-hook 'magit-load-config-extensions)

;; full screen magit-status
(defadvice magit-status (around magit-fullscreen activate)
  (window-configuration-to-register :magit-fullscreen)
  ad-do-it
  (delete-other-windows))

(global-unset-key (kbd "C-x g"))
(global-set-key (kbd "C-x g h") 'magit-log)
(global-set-key (kbd "C-x g f") 'magit-file-log)
(global-set-key (kbd "C-x g b") 'magit-blame-mode)
(global-set-key (kbd "C-x g m") 'magit-branch-manager)
(global-set-key (kbd "C-x g c") 'magit-branch)
(global-set-key (kbd "C-x g s") 'magit-status)
(global-set-key (kbd "C-x g r") 'magit-reflog)
(global-set-key (kbd "C-x g t") 'magit-tag)

Usage:

Getting started with Magit is really easy:

• M-x magit-status to see git status, and in the status buffer:
• s to stage files
• c c to commit, type in your commit message then C-c C-c to save the message and commit, C-c C-k to abort current commit message and go back magit-status.
• b b to switch to a branch.

Other handy keys:

• P P to do a git push
• F F to do a git pull
• try to press TAB on entries.

If you want to view the raw git commands, i.e. you want to know how git push is doing, press $.

For more usage, please refer to the official manual.

Author: Sebastian Wiesner, swiesner@lunaryorn.com

Homepage: http://flycheck.readthedocs.org/

Features:

• Supports over 30 programming and markup languages with more than 60 different syntax checking tools
• Fully automatic, fail-safe, on-the-fly syntax checking in background
• Nice error indication and highlighting
• Optional error list popup
• Many customization options
• A comprehensive manual
• A simple interface to define new syntax checkers
• A “doesn't get in your way” guarantee
• Many 3rd party extensions

Installation;

M-x list-packages and select flycheck package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; PACKAGE: flycheck                       ;;
;;                                         ;;
;; GROUP: Programming -> Tools -> Flycheck ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(require 'flycheck)
(add-hook 'after-init-hook #'global-flycheck-mode)

Usage:

After you installed and activated flycheck, your supported buffers are automatically checked against errors as you typed and the errors are displayed in echo area.

Author: Yuta Yamada, cokesboy@gmail.com

Homepage: Github

Features:

Show flycheck error by popupo.

Installation: M-x list-packages and select flycheck-tip package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; PACKAGE: flycheck-tip                                      ;;
;;                                                            ;;
;; GROUP: Flycheck Tip, but just consider it part of Flycheck ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(require 'flycheck-tip)
(flycheck-tip-use-timer 'verbose)

Usage:

The errors are now displayed by popup, instead of printing into the echo area. Echo area should be preserved for other things like eldoc-mode.

Author: Jacek "TeMPOraL" Zlydach, temporal.pl@gmail.com

Homepage: http://nyan-mode.buildsomethingamazing.com/

Features:

Nyan Mode is an analog indicator of your position in the buffer. The Cat should go from left to right in your mode-line, as you move your point from 0% to 100%.

• Mind dumbing content included,
• Experimental animation (M-x nyan-start-animation, M-x nyan-stop-animation),
• Wavy rainbow (M-x set-variable <ret> nyan-wavy-trail <ret> t),
• Customizable properties.

NOT INCLUDED: music.

Installation:

M-x list-packages and select nyan-mode package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; PACKAGE: nyan-mode                    ;;
;;                                       ;;
;; GROUOP: Environment -> Frames -> Nyan ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; only turn on if a window system is available
;; this prevents error under terminal that does not support X
(case window-system
  ((x w32) (nyan-mode)))

Usage:

As you scroll through a buffer, the cat moves to indicate the position in buffer.

Author: Roman Gonzalez, romanandreg@gmail.com

Homepage: Github

Features:

Automatic resizing of Emacs windows to the golden ratio

When working with many windows at the same time, each window has a size that is not convenient for editing.

golden-ratio helps on this issue by resizing automatically the windows you are working on to the size specified in the "Golden Ratio". The window that has the main focus will have the perfect size for editing, while the ones that are not being actively edited will be re-sized to a smaller size that doesn't get in the way, but at the same time will be readable enough to know it's content.

Installation:

M-x list-packages and select golden-ratio package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; PACKAGE: golden-ratio                         ;;
;;                                               ;;
;; GROUP: Environment -> Windows -> Golden Ratio ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(require 'golden-ratio)

(add-to-list 'golden-ratio-exclude-modes "ediff-mode")
(add-to-list 'golden-ratio-exclude-modes "helm-mode")
(add-to-list 'golden-ratio-exclude-modes "dired-mode")
(add-to-list 'golden-ratio-inhibit-functions 'pl/helm-alive-p)

(defun pl/helm-alive-p ()
  (if (boundp 'helm-alive-p)
      (symbol-value 'helm-alive-p)))

;; do not enable golden-raio in thses modes
(setq golden-ratio-exclude-modes '("ediff-mode"
                                   "gud-mode"
                                   "gdb-locals-mode"
                                   "gdb-registers-mode"
                                   "gdb-breakpoints-mode"
                                   "gdb-threads-mode"
                                   "gdb-frames-mode"
                                   "gdb-inferior-io-mode"
                                   "gud-mode"
                                   "gdb-inferior-io-mode"
                                   "gdb-disassembly-mode"
                                   "gdb-memory-mode"
                                   "magit-log-mode"
                                   "magit-reflog-mode"
                                   "magit-status-mode"
                                   "IELM"
                                   "eshell-mode" "dired-mode"))

(golden-ratio-mode)

Usage:

C-x o and see your windows being resized.

Author: Fanael Linithien, fanael4@gmail.com

Homepage: Github

Features:

highlight-numbers is an Emacs minor mode that highlights numeric literals in source code.

Installation:

M-x list-packages and select highlight-numbers package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; PACKAGE: highlight-numbers         ;;
;;                                    ;;
;; GROUP: Faces -> Number Font Lock   ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(add-hook 'prog-mode-hook 'highlight-numbers-mode)

Usage:

Numbers automatically have distinct colors in buffer.

Author: Nikolaj Schumacher, me@nschum.de

Homepage: Github

Features:

Automatic and manual symbol highlighting for Emacs.

Installation:

M-x list-packages and select highlight-symbol package, then install it. After finish installing, add this code snippet to activate the package:

(require 'highlight-symbol)

(highlight-symbol-nav-mode)

(add-hook 'prog-mode-hook (lambda () (highlight-symbol-mode)))
(add-hook 'org-mode-hook (lambda () (highlight-symbol-mode)))

(setq highlight-symbol-idle-delay 0.2
      highlight-symbol-on-navigation-p t)

(global-set-key [(control shift mouse-1)]
                (lambda (event)
                  (interactive "e")
                  (goto-char (posn-point (event-start event)))
                  (highlight-symbol-at-point)))

(global-set-key (kbd "M-n") 'highlight-symbol-next)
(global-set-key (kbd "M-p") 'highlight-symbol-prev)

Usage:

If you move point on a symbol, it automatically highlights all the symbols in the current screen. From now on, pressing M-n and M-p will immediately jump to the next/previous symbols in a buffer.

Emacs has many color themes available for you to use. My personal one is color-theme-sanityinc-tomorrow or grandshell-theme or monokai-theme. Some popular themes are emacs-color-theme-solarized and zenburn. You can select themes of your choice from MELPA.

Author: Drew Adams, drew.adams@oracle.com

Homepage: Emacswiki

Features: Info+ helps you read Info documents more enjoyable with extra highlighting it provides.

Installation:

M-x list-packages and select info+ package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; GROUP: Help -> Info+               ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(require 'info+)

Author: steckerhalter

Homepage: Github

Features:

Discover key bindings and their meaning for the current Emacs major mode.

Installation:

M-x list-packages and select discover-my-major package, then install it. After finish installing, add this code snippet to activate the package:

;; A quick major mode help with discover-my-major
(global-unset-key (kbd "C-h h"))        ; original "C-h h" displays "hello world" in different languages
(define-key 'help-command (kbd "h m") 'discover-my-major)

Usage:

The above setup binds C-h h m to discover-my-major. In a buffer, C-h h m and you will see key bindings of that major mode and its description, as opposed to usual C-h m which gives mappings between keys and commands.

Author: Julien Danjou, julien@danjou.info

Homepage: GNU ELPA

Features:

This minor mode sets background color to strings that match color names, e.g. #0000ff is displayed in white with a blue background.

Installation: M-x list-packages and select rainbow-mode package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; PACKAGE: rainbow-mode              ;;
;;                                    ;;
;; GROUP: Help -> Rainbow             ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(add-hook 'html-mode-hook 'rainbow-mode)
(add-hook 'css-mode-hook 'rainbow-mode)

It is useful to always activate rainbow-mode in those two major modes. For other modes, it is situational, so I don't use prog-mode-hook.

Usage:

As you type a hex number or a color string in a buffer with rainbow-mode activated, the hex number or color string is colourized.

Author: Drew Adams, drew.adams@oracle.com

Homepage: Emacswiki

Features:

Extensions to `help.el' for Emacs

Installation:

M-x list-packages and select help+ package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Package: help+                     ;;
;;                                    ;;
;; GROUP: Help                        ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(require 'help+)

Usage:

The following bindings are made:

`C-h u' `manual-entry' `C-h C-a' `apropos' `C-h C-l' `locate-library' `C-h RET' `help-on-click/key' `C-h M-a' `apropos-documentation' `C-h M-o' `pop-to-help-toggle' `C-h C-M-a' `tags-apropos' [mouse-1] `mouse-help-on-click' (non-mode-line) [mouse-1] `mouse-help-on-mode-line-click' (mode-line)

Author: Drew Adams, drew.adams@oracle.com

Homepage: Emacswiki

Features:

Extensions to `help-fns.el'

Installation:

M-x list-packages and select help-fns+ package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Package: help-fns+                 ;;
;;                                    ;;
;; GROUP: Help                        ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(require 'help-fns+)

Usage:

Keys bound here:

Author: Drew Adams, drew.adams@oracle.com

Homepage: Emacswiki

Features:

Extensions to `help-mode.el'

Links to libraries are provided whenever library names appear in buffer ‘*Help*’. After loading help-mode+.el, library names in buffer Help have mouse-over links to the corresponding library code.

For example, ‘C-h v features’ describes the variable ‘features’; this description lists all of the libraries currently loaded in Emacs.

• In vanilla Emacs (without help-mode+.el loaded), the library names are not linked, unless a library (such as ‘grep’) happens to have the same name as an Emacs function or variable, in which case clicking the name displays the function or variable description in buffer Help.
• With help-mode+.el loaded, each library name in the ‘C-h v features’ list is linked to the library (code) itself. Click a name to edit/view the library file.

Installation:

M-x list-packages and select help-mode+ package, then install it. After finish installing, add this code snippet to activate the package:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Package: help-mode+                ;;
;;                                    ;;
;; GROUP: Help                        ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(require 'help-mode+)

Usage:

If a *Help* buffer contains other library names, the names automatically becomes links to jump to.