This is part of oh-my-emacs.
| Package | Status | Description |
|---|---|---|
| auto-complete | Required | I really like it. |
| helm | Required | Completion everywhere, highly recommended. |
| YASnippet | Required | Quick snippet template insertion. |
| pos-tip | Required | For better auto-complete popup tips window. |
M-x hippie-expand is a single command providing a variety of completions and
expansions. The following code segment comes from Emacs Prelude.
;; hippie expand is dabbrev expand on steroids
(setq hippie-expand-try-functions-list '(try-expand-dabbrev
try-expand-dabbrev-all-buffers
try-expand-dabbrev-from-kill
try-complete-file-name-partially
try-complete-file-name
try-expand-all-abbrevs
try-expand-list
try-expand-line
try-complete-lisp-symbol-partially
try-complete-lisp-symbol))Auto-Complete is an intelligent auto-completion extension for Emacs. It extends the standard Emacs completion interface and provides an environment that allows users to concentrate more on their own work.
Actually, there’re multiple completion packages for Emacs, say Emacs builtin
completion, there’re completion-at-point function for completion in buffers,
pcomplete for completion mainly for comint-mode, such as completion in
Eshell, ido-mode for completion in minibuffers. Say auto-complete, there’s
also a competitive company-mode.
By default, function global-auto-complete-mode will toggle on auto-complete
according to ac-modes, which in turn determines what major mode
auto-complete-mode can run on. Oh-my-emacs add org-mode and text-mode to
ac-modes.
(defun ome-auto-complete-setup ()
(require 'auto-complete-config)
(define-key ac-mode-map (kbd "M-/") 'ac-fuzzy-complete)
(dolist (ac-mode '(text-mode org-mode))
(add-to-list 'ac-modes ac-mode))
(dolist (ac-mode-hook '(text-mode-hook org-mode-hook prog-mode-hook))
(add-hook ac-mode-hook
(lambda ()
(setq ac-fuzzy-enable t)
(add-to-list 'ac-sources 'ac-source-files-in-current-dir)
(add-to-list 'ac-sources 'ac-source-filename))))
(ac-config-default))
(ome-install 'auto-complete)You may wonder why oh-my-emacs choose auto-complete? In a word, auto-complete
is flexible which provides a plugin mechanism through which you can define your
own ac-source, thus you get unlimited possibilities to complete in various
programming languages, major modes, etc.
The following code comes from EmacsWiki, which defines a ac-source-pcomplete
that integrates pcomplete as a completion backend to auto-complete.
(defun ac-pcomplete ()
;; eshell uses `insert-and-inherit' to insert a \t if no completion
;; can be found, but this must not happen as auto-complete source
(flet ((insert-and-inherit (&rest args)))
;; this code is stolen from `pcomplete' in pcomplete.el
(let* (tramp-mode ;; do not automatically complete remote stuff
(pcomplete-stub)
(pcomplete-show-list t) ;; inhibit patterns like * being deleted
pcomplete-seen pcomplete-norm-func
pcomplete-args pcomplete-last pcomplete-index
(pcomplete-autolist pcomplete-autolist)
(pcomplete-suffix-list pcomplete-suffix-list)
(candidates (pcomplete-completions))
(beg (pcomplete-begin))
;; note, buffer text and completion argument may be
;; different because the buffer text may bet transformed
;; before being completed (e.g. variables like $HOME may be
;; expanded)
(buftext (buffer-substring beg (point)))
(arg (nth pcomplete-index pcomplete-args)))
;; we auto-complete only if the stub is non-empty and matches
;; the end of the buffer text
(when (and (not (zerop (length pcomplete-stub)))
(or (string= pcomplete-stub ; Emacs 23
(substring buftext
(max 0
(- (length buftext)
(length pcomplete-stub)))))
(string= pcomplete-stub ; Emacs 24
(substring arg
(max 0
(- (length arg)
(length pcomplete-stub)))))))
;; Collect all possible completions for the stub. Note that
;; `candidates` may be a function, that's why we use
;; `all-completions`.
(let* ((cnds (all-completions pcomplete-stub candidates))
(bnds (completion-boundaries pcomplete-stub
candidates
nil
""))
(skip (- (length pcomplete-stub) (car bnds))))
;; We replace the stub at the beginning of each candidate by
;; the real buffer content.
(mapcar #'(lambda (cand) (concat buftext (substring cand skip)))
cnds))))))
(defvar ac-source-pcomplete
'((candidates . ac-pcomplete)))Semantic completion based on auto-complete is one of the major goals of oh-my-emacs. The following matrix show the current status of oh-my-emacs semantic completion.
| AC Usability | AC Backend | Detail | |
|---|---|---|---|
| C/C++ | 80% | auto-complete-clang | Issue with function argument list. |
| Python | 100% | elpy | elpy is amazing. |
| Emacs Lisp | 100% | Builtin | You kown that. |
| Common Lisp | 100% | ac-slime | SLIME is amazing, too. |
| Scheme | 80% | ac-geiser | Yeah, I’m the author of ac-geiser. |
| Clojure | 100% | ac-nrepl | It even completes Java! |
Helm is a incremental completion and selection narrowing framework for
emacs. It will help steer you in the right direction when you’re looking for
stuff in Emacs (like buffers, files, etc). Helm is a fork of anything.el,
which clean up the legacy code in anything.el and provide a cleaner and more
modular tool.
Actually, helm is not the only name completion packages in emacs, there’re other choices–of course you always have choices in emacs, for example, the builtin ido-mode is quite a good choice. I also heard of icicles to be the most powerful, but I found its documentatin really awkward. I choose helm since it is easy to install and config, user-friendly, powerful enough and quite intuitive to boost your workflow.
To tell the truth, I, myself, the author of oh-my-emacs, is a heavy user of
helm and never wish to go back to life with ido or some fuzzy match
packages. Helm is one of my favourite emacs packages. The more you live with
helm, the more you will find that you never want to go back. Helm can replace
many builtin or third-party emacs packages, or even provide a better
experience. For example, helm-M-x is a good competitor to smex,
helm-show-kill-ring provides a better way to interact with emacs kill ring
than browse-kill-ring. Helm integrates various external tools(such as grep,
find, locate, md5sum, etags, etc.) to emacs in a highly intuitive and
interactive way. Helm can even help you install debian apt packages. If you
have any question, just type M-x helm-google-suggest and then helm will fire
a web browser opening google for you at your fingertip.
And I’ve found a really great and awesome post written by tuhdo@github, which demonstrate how powerful helm is with an intuitive way by posting lots of GIF images. I highly recommend you to read this post and I’m sure that you will fall in love with helm and never look back, just like me.
I’ve also borrow lots of code from that post and make some incompatible changes
about how to use helm in oh-my-emacs. One of the most important is,
oh-my-emacs now binds helm-execute-persistent-action to TAB and
helm-select-action to C-z, and also, you should use C-o to go to
different “categories” in helm list, since oh-my-emacs set
helm-move-to-line-cycle-in-source to t, check docs for details.
To wrap your mind around the helm way, you need to remember a few key bindings. When helm starts, remember:
- access the helm action menu with
C-z. Maybe this is the most whirlwind turnaround since most name completion packages useTABas completion key. Don’t worry, helm doesn’t need too much completion, since helm provides name completion by navigation instead by usingTABto complete character by character. Actually, the helmTABbrings you a new world, in which you combine several tasks into a series of successive keystrokes and get your job done. - Use persistent actions with
TAB. - Mark candidate with
M-<SPACE>, thus you can do batch processing through helm.
The helm wiki is a good place to explore this new world, but it’s a little long and not complete enough to cover all helm power. You can access helm functions through the emacs menubar if want to use helm but don’t want to remember too much helm key bindings. Some shortcuts:
C-x c l:helm-locateC-x c /:helm-findC-x c f:helm-for-filesC-x c M-x:helm-M-xC-x c a:helm-aproposC-x c r:helm-regexpC-x c c:helm-colorsC-x c 8:helm-ucsC-x c i:helm-imenuC-x c m:helm-man-womanC-x c t:helm-topC-x c p:helm-list-emacs-processC-x c M-y:helm-show-kill-ring
To fully adopt helm power, I also set some custom helm keybindings in
oh-my-emacs, you can change it as you like. Of course you can disable helm at
all, then oh-my-emacs will use some other packages such as ido-mode as a
fallback. But I do suggest you to take some time to be familiar with helm.
(defun ome-helm-setup ()
(require 'helm-config)
(setq helm-input-idle-delay 0.2)
(helm-mode t)
(setq helm-locate-command
(case system-type
('gnu/linux "locate -i -r %s")
('berkeley-unix "locate -i %s")
('windows-nt "es %s")
('darwin "mdfind -name %s %s")
(t "locate %s")))
(global-set-key (kbd "C-x c g") 'helm-do-grep)
(global-set-key (kbd "C-x c o") 'helm-occur)
(global-set-key (kbd "M-x") 'helm-M-x)
(global-set-key (kbd "C-x C-f") 'helm-find-files)
;; rebind tab to run persistent action
(define-key helm-map (kbd "<tab>") 'helm-execute-persistent-action)
;; make TAB works in terminal
(define-key helm-map (kbd "C-i") 'helm-execute-persistent-action)
;; list actions using C-z
(define-key helm-map (kbd "C-z") 'helm-select-action)
(when (executable-find "curl")
(setq helm-google-suggest-use-curl-p t))
(setq
;; open helm buffer inside current window, not occupy whole other window
helm-split-window-in-side-p t
;; fuzzy matching buffer names when non--nil
helm-buffers-fuzzy-matching t
;; move to end or beginning of source when reaching top or bottom of source.
helm-move-to-line-cycle-in-source t
;; search for library in `require' and `declare-function' sexp.
helm-ff-search-library-in-sexp t
;; scroll 8 lines other window using M-<next>/M-<prior>
helm-scroll-amount 8
helm-ff-file-name-history-use-recentf t))
(ome-install 'helm)
Helm Descbinds provides an interface to emacs’ describe-bindings making the currently active key bindings interactively searchable with helm.
Additionally you have the following helm persistent actions
- Execute the command
- Describe the command
- Find the command
(defun ome-helm-descbinds-setup ()
(helm-descbinds-mode 1))
(ome-install 'helm-descbinds)YASnippet is “Yet Another Snippet” expansion system for Emacs. It is inspired by TextMate’s templating syntax. You can see the intro and tutorial or watch this video on youtube to get some basic knowledge.
Oh-my-emacs do some hacks to yas-prompt-functions, it adopts popup, a visual
popup interface library extracted from auto-complete by its author. It has
better look and feel than all the built-in yas-prompt-functions. Also it is
easy to customize, and its isearch mode is very efficient, the items are
filtered on-the-fly when typing[1].
TODO:
- The bundled snippets from official yasnippet is considered frozen, so you should add your own snippets if you want more. Maybe yasnippet-snippets is a good starting point, but I think it’s far from perfect, for example, the emacs-lisp snippet is not quite hard to use.
(eval-after-load 'popup
'(progn
(define-key popup-menu-keymap (kbd "M-n") 'popup-next)
(define-key popup-menu-keymap (kbd "TAB") 'popup-next)
(define-key popup-menu-keymap (kbd "<tab>") 'popup-next)
(define-key popup-menu-keymap (kbd "<backtab>") 'popup-previous)
(define-key popup-menu-keymap (kbd "M-p") 'popup-previous)))
(defun yas-popup-isearch-prompt (prompt choices &optional display-fn)
(when (featurep 'popup)
(popup-menu*
(mapcar
(lambda (choice)
(popup-make-item
(or (and display-fn (funcall display-fn choice))
choice)
:value choice))
choices)
:prompt prompt
;; start isearch mode immediately
:isearch t)))
(defun ome-yasnippet-setup ()
(setq yas-prompt-functions
'(yas-popup-isearch-prompt
yas-no-prompt))
(yas-global-mode))
(ome-install 'popup)
(ome-install 'yasnippet)Ah, various ideas to enhance helm:
- Provide a copy action which just copy the selected items. This is useful when you query a elisp command or function.
- Provide a doc action which show documentation of elisp function or commands.
- For helm-projectile, add full path to file list to differentiate same file name files.
[1] http://iany.me/2012/03/use-popup-isearch-for-yasnippet-prompt/