Corfu enhances in-buffer completion with a small completion popup. The current candidates are shown in a popup below or above the point. The candidates can be selected by moving up and down. Corfu is the minimalistic in-buffer completion counterpart of the Vertico minibuffer UI.
Corfu is a small package, which relies on the Emacs completion facilities and
concentrates on providing a polished completion UI. In-buffer completion UIs in
Emacs can hook into
completion-in-region, which implements the interaction with
the user. Completions at point are either provided by commands like
dabbrev-completion or by pluggable backends (
Capfs) and are then passed to
completion-in-region. Many programming, text and
shell major modes implement a Capf. Corfu does not include its own completion
backends. The Emacs built-in Capfs and the Capfs provided by third-party
programming language packages are often sufficient. Additional Capfs and
completion utilities are provided by the Cape package.
NOTE: Corfu uses child frames to show the popup and falls back to the default
setting of the
completion-in-region-function on non-graphical displays. If you
want to use Corfu in the terminal, install the package corfu-terminal, which
provides an alternative overlay-based display.
Corfu is available from GNU ELPA, such that it can be installed directly via
package-install. After installation, the global minor mode can be enabled with
‘M-x global-corfu-mode’. In order to configure Corfu and other packages in your
init.el, you may want to use
Corfu is highly flexible and customizable via
corfu-* customization variables,
such that you can adapt it precisely to your requirements. However in order to
quickly try out the Corfu completion package, it should be sufficient to
global-corfu-mode. You can experiment with manual completion for
example in an Elisp buffer or in an Eshell or Shell buffer. For auto completion,
corfu-auto to t before turning on
Here is an example configuration:
(use-package corfu ;; Optional customizations ;; :custom ;; (corfu-cycle t) ;; Enable cycling for `corfu-next/previous' ;; (corfu-auto t) ;; Enable auto completion ;; (corfu-separator ?\s) ;; Orderless field separator ;; (corfu-quit-at-boundary nil) ;; Never quit at completion boundary ;; (corfu-quit-no-match nil) ;; Never quit, even if there is no match ;; (corfu-preview-current nil) ;; Disable current candidate preview ;; (corfu-preselect 'prompt) ;; Preselect the prompt ;; (corfu-on-exact-match nil) ;; Configure handling of exact matches ;; (corfu-scroll-margin 5) ;; Use scroll margin ;; Enable Corfu only for certain modes. ;; :hook ((prog-mode . corfu-mode) ;; (shell-mode . corfu-mode) ;; (eshell-mode . corfu-mode)) ;; Recommended: Enable Corfu globally. ;; This is recommended since Dabbrev can be used globally (M-/). ;; See also `global-corfu-modes'. :init (global-corfu-mode)) ;; A few more useful configurations... (use-package emacs :init ;; TAB cycle if there are only few candidates (setq completion-cycle-threshold 3) ;; Emacs 28: Hide commands in M-x which do not apply to the current mode. ;; Corfu commands are hidden, since they are not supposed to be used via M-x. ;; (setq read-extended-command-predicate ;; #'command-completion-default-include-p) ;; Enable indentation+completion using the TAB key. ;; `completion-at-point' is often bound to M-TAB. (setq tab-always-indent 'complete))
Dabbrev completion is based on ‘completion-in-region’ and can be used with Corfu. You may want to swap the ‘dabbrev-completion’ with the ‘dabbrev-expand’ key for easier access, if you prefer completion. Also take a look at the ‘cape-dabbrev’ completion at point function provided by my Cape package.
;; Use Dabbrev with Corfu! (use-package dabbrev ;; Swap M-/ and C-M-/ :bind (("M-/" . dabbrev-completion) ("C-M-/" . dabbrev-expand)) ;; Other useful Dabbrev configurations. :custom (dabbrev-ignored-buffer-regexps '("\\.\\(?:pdf\\|jpe?g\\|png\\)\\'")))
If you start to configure the package more deeply, I recommend to give the Orderless completion style a try for filtering. Orderless completion is different from the familiar prefix TAB completion. Corfu can be used with the default completion styles. The use of Orderless is not a necessity.
;; Optionally use the `orderless' completion style. (use-package orderless :init ;; Configure a custom style dispatcher (see the Consult wiki) ;; (setq orderless-style-dispatchers '(+orderless-dispatch) ;; orderless-component-separator #'orderless-escapable-split-on-space) (setq completion-styles '(orderless basic) completion-category-defaults nil completion-category-overrides '((file (styles partial-completion)))))
The ‘basic’ completion style is specified as fallback in addition to ‘orderless’ in
order to ensure that completion commands which rely on dynamic completion
correctly. See ‘+orderless-dispatch’ in the Consult wiki for an advanced Orderless
style dispatcher. Additionally enable ‘partial-completion’ for file path
expansion. ‘partial-completion’ is important for file wildcard support. Multiple
files can be opened at once with ‘find-file’ if you enter a wildcard. You may also
give the ‘initials’ completion style a try.
See also the Corfu Wiki and the Cape manual for additional Capf configuration tips. The language server protocol (LSP) configurations are documented in the wiki. For more general documentation read the chapter about completion in the Emacs manual. If you want to create your own Capfs, you can find documentation about completion in the Elisp manual.
Auto completion is disabled by default, but can be enabled by setting
to t. Furthermore you may want to configure Corfu to quit completion eagerly,
such that the completion popup stays out of your way when it appeared
;; Enable auto completion and configure quitting (setq corfu-auto t corfu-quit-no-match 'separator) ;; or t
I recommend to experiment a bit with the various settings and key bindings to find a configuration which works for you. There is no one size fits all solution. Some people like auto completion, some like manual completion, some want to cycle with TAB and some with the arrow keys.
In case you like aggressive auto completion settings, where the completion popup appears immediately, I recommend to use a cheap completion style like ‘basic’, which performs prefix filtering. In this case Corfu completion should still be very fast in buffers with efficient completion backends. You can try the following settings in an Elisp buffer or the Emacs scratch buffer.
;; Aggressive completion, cheap prefix filtering. (setq-local corfu-auto t corfu-auto-delay 0 corfu-auto-prefix 0 completion-styles '(basic))
If you want to combine fast prefix filtering and Orderless filtering you can still do that by defining a custom Orderless completion style via ‘orderless-define-completion-style’. We use a custom style dispatcher, which enables efficient prefix filtering for input shorter than 4 characters. Note that such a setup is advanced. Please refer to the Orderless documentation and source code for further details.
(defun orderless-fast-dispatch (word index total) (and (= index 0) (= total 1) (length< word 4) `(orderless-regexp . ,(concat "^" (regexp-quote word))))) (orderless-define-completion-style orderless-fast (orderless-style-dispatchers '(orderless-fast-dispatch)) (orderless-matching-styles '(orderless-literal orderless-regexp))) (setq-local corfu-auto t corfu-auto-delay 0 corfu-auto-prefix 1 completion-styles '(orderless-fast basic))
Corfu can be used for completion in the minibuffer, since it relies on child
frames to display the candidates. By default,
global-corfu-mode does not
corfu-mode in the minibuffer, to avoid interference with specialised
minibuffer completion UIs like Vertico or Mct. However you may still want to
enable Corfu completion for commands like
shell-command), which read from the minibuffer. Activate
corfu-mode only if
completion-at-point is bound in the minibuffer-local keymap to achieve this
(defun corfu-enable-in-minibuffer () "Enable Corfu in the minibuffer if `completion-at-point' is bound." (when (where-is-internal #'completion-at-point (list (current-local-map))) ;; (setq-local corfu-auto nil) ;; Enable/disable auto completion (setq-local corfu-echo-delay nil ;; Disable automatic echo and popup corfu-popupinfo-delay nil) (corfu-mode 1))) (add-hook 'minibuffer-setup-hook #'corfu-enable-in-minibuffer)
You can also enable Corfu more generally for every minibuffer, as long as no completion UI is active. In the following example we check for Mct and Vertico. Furthermore we ensure that Corfu is not enabled if a password is read from the minibuffer.
(defun corfu-enable-always-in-minibuffer () "Enable Corfu in the minibuffer if Vertico/Mct are not active." (unless (or (bound-and-true-p mct--active) (bound-and-true-p vertico--input) (eq (current-local-map) read-passwd-map)) ;; (setq-local corfu-auto nil) ;; Enable/disable auto completion (setq-local corfu-echo-delay nil ;; Disable automatic echo and popup corfu-popupinfo-delay nil) (corfu-mode 1))) (add-hook 'minibuffer-setup-hook #'corfu-enable-always-in-minibuffer 1)
When completing in the Eshell I recommend conservative local settings without auto completion, such that the completion behavior is similar to widely used shells like Bash, Zsh or Fish.
(add-hook 'eshell-mode-hook (lambda () (setq-local corfu-auto nil) (corfu-mode)))
When pressing ‘RET’ while the Corfu popup is visible, the
will be invoked. This command does inserts the currently selected candidate, but
it does not send the prompt input to Eshell or the Comint process. Therefore you
often have to press ‘RET’ twice which feels like an unnecessary double
confirmation. Fortunately it is easy to improve this! In my configuration I
define the advice
corfu-send-shell which sends the candidate after insertion.
(defun corfu-send-shell (&rest _) "Send completion candidate when inside comint/eshell." (cond ((and (derived-mode-p 'eshell-mode) (fboundp 'eshell-send-input)) (eshell-send-input)) ((and (derived-mode-p 'comint-mode) (fboundp 'comint-send-input)) (comint-send-input)))) (advice-add #'corfu-insert :after #'corfu-send-shell)
Shell completion uses the flexible Pcomplete mechanism internally, which allows you to program the completions per shell command. If you want to know more, look into this blog post, which shows how to configure Pcomplete for git commands.
I recommend the pcmpl-args package which extends Pcomplete with completion
support and helpful annotation support for more commands. Similar to the Fish
shell, ‘pcmpl-args’ uses man page parsing and
--help output parsing to dynamically
generate completions. This package brings Eshell completion to another level!
Since Emacs 29, Pcomplete offers the ‘pcomplete-from-help’ function which parses
--help output of a command and produces completions. This Emacs 29
functionality is not completely equivalent. For example it does not display
annotations in Eshell, but this may get fixed in Emacs 30.
Pcomplete has a few bugs on Emacs 28 and older. We can work around the issues with the Cape library (Completion at point extensions). Cape provides wrappers which sanitize the Pcomplete function. If you use Emacs 28 or older installing these advices is recommended such that Pcomplete works properly. On Emacs 29 the advices should not be necessary anymore, since most of the relevant bugs have been fixed. I therefore recommend to remove the advices on Emacs 29 and eventually report any remaining Pcomplete issues upstream, such that they can be fixed.
;; The advices are only needed on Emacs 28 and older. (when (< emacs-major-version 29) ;; Silence the pcomplete capf, no errors or messages! (advice-add 'pcomplete-completions-at-point :around #'cape-wrap-silent) ;; Ensure that pcomplete does not write to the buffer ;; and behaves as a pure `completion-at-point-function'. (advice-add 'pcomplete-completions-at-point :around #'cape-wrap-purify))
Orderless is an advanced completion style that supports multi-component search filters separated by a configurable character (space, by default). Normally, entering characters like space which lie outside the completion region boundaries (words, typically) causes Corfu to quit. This behavior is helpful with auto-completion, which may pop-up when not desired, e.g. on entering a new variable name. Just keep typing and Corfu will get out of the way.
But orderless search terms can contain arbitrary characters; they are also
interpreted as regular expressions. To use orderless, set
space, by default) to the primary character of your orderless component
Then, when a new orderless component is desired, use ‘M-SPC’
corfu-insert-separator) to enter the first component separator in the input,
and arbitrary orderless search terms and new separators can be entered
To treat the entire input as Orderless input, you can set the customization
corfu-quit-at-boundary to t. This disables the predicate which checks if
the current completion boundary has been left. In contrast, if you always want
to quit at the boundary, set
nil. By default
corfu-quit-at-boundary is set to
separator which quits at completion boundaries
as long as no separator has been inserted with
Finally, there exists the user option
corfu-quit-no-match which is set to
‘separator’ by default. With this setting Corfu stays alive as soon as you start
advanced filtering with a
corfu-separator even if there are no matches, for
example due to a typo. As long as no separator character has been inserted with
corfu-insert-separator, Corfu will still quit if there are no matches. This
ensures that the Corfu popup goes away quickly if completion is not possible.
In the following we show two configurations, one which works best with auto completion and one which may work better with manual completion if you prefer to always use ‘SPC’ to separate the Orderless components.
;; Auto completion example (use-package corfu :custom (corfu-auto t) ;; Enable auto completion ;; (corfu-separator ?_) ;; Set to orderless separator, if not using space :bind ;; Another key binding can be used, such as S-SPC. ;; (:map corfu-map ("M-SPC" . corfu-insert-separator)) :init (global-corfu-mode)) ;; Manual completion example (use-package corfu :custom ;; (corfu-separator ?_) ;; Set to orderless separator, if not using space :bind ;; Configure SPC for separator insertion (:map corfu-map ("SPC" . corfu-insert-separator)) :init (global-corfu-mode))
By default, Corfu steals both the
TAB keys, when the Corfu popup is
open. This can feel intrusive, in particular in combination with auto
RET may accidentally commit an automatically selected candidate,
while you actually wanted to start a new line. As an alternative we can unbind
RET key completely from
corfu-map or reserve the
RET key only in shell
;; TAB-only configuration (use-package corfu :custom (corfu-auto t) ;; Enable auto completion (corfu-preselect 'directory) ;; Select the first candidate, except for directories ;; Free the RET key for less intrusive behavior. :bind (:map corfu-map ;; Option 1: Unbind RET completely ;;; ("RET" . nil) ;; Option 2: Use RET only in shell modes ("RET" . (menu-item "" nil :filter corfu-insert-shell-filter))) :init (global-corfu-mode)) (defun corfu-insert-shell-filter (&optional _) "Insert completion candidate and send when inside comint/eshell." (when (derived-mode-p 'eshell-mode 'comint-mode) (lambda () (interactive) (corfu-insert) ;; `corfu-send-shell' was defined above (corfu-send-shell))))
You may be interested in configuring Corfu in TAB-and-Go style. Pressing TAB
moves to the next candidate and further input will then commit the selection.
Note that further input will not expand snippets or templates, which may not be
desired but which leads overall to a more predictable behavior. In order to
force snippet expansion, confirm a candidate explicitly with
(use-package corfu ;; TAB-and-Go customizations :custom (corfu-cycle t) ;; Enable cycling for `corfu-next/previous' (corfu-preselect 'prompt) ;; Always preselect the prompt ;; Use TAB for cycling, default is `corfu-complete'. :bind (:map corfu-map ("TAB" . corfu-next) ([tab] . corfu-next) ("S-TAB" . corfu-previous) ([backtab] . corfu-previous)) :init (global-corfu-mode))
Sometimes it is useful to transfer the Corfu completion session to the minibuffer, since the minibuffer offers richer interaction features. In particular, Embark is available in the minibuffer, such that you can act on the candidates or export/collect the candidates to a separate buffer. We could add Corfu support to Embark in the future, such that export/collect is possible directly from Corfu. But in my opinion having the ability to transfer the Corfu completion to the minibuffer is an even better feature, since further completion can be performed there.
corfu-move-to-minibuffer is defined here in terms of
consult-completion-in-region, which uses the minibuffer completion UI via
(defun corfu-move-to-minibuffer () (interactive) (when completion-in-region--data (let ((completion-extra-properties corfu--extra) completion-cycle-threshold completion-cycling) (apply #'consult-completion-in-region completion-in-region--data)))) (keymap-set corfu-map "M-m" #'corfu-move-to-minibuffer) (add-to-list 'corfu-continue-commands #'corfu-move-to-minibuffer)
Corfu uses a transient keymap
corfu-map which is active while the popup is
shown. The keymap defines the following remappings and bindings:
next-line, ‘down’, ‘M-n’ ->
previous-line, ‘up’, ‘M-p’ ->
completion-at-point, ‘TAB’ ->
We maintain small extension packages to Corfu in this repository in the
subdirectory extensions/. The extensions are installed together with Corfu if
you pull the package from ELPA. The extensions are inactive by default and can
be enabled manually if desired. Furthermore it is possible to install all of the
files separately, both
corfu.el and the
corfu-*.el extensions. Currently the
following extensions come with the Corfu ELPA package:
See the Commentary of those files for configuration details.
Corfu works well together with all packages providing code completion via the
completion-at-point-functions. Many modes and packages already provide a Capf
out of the box. Nevertheless you may want to look into complementary packages to
enhance your setup.
cape-company-to-capfadapter to reuse Company backends in Corfu.
company-capfto handle Capfs as a Company backend. As a result of this design, Company is a more complex package than Corfu. Company by default uses overlays for the popup in contrast to the child frames used by Corfu. Overall both packages work well, but Company integrates less tightly with Emacs. The
completion-stylessupport is more limited and the
completion-at-pointcommand and the
completion-in-regionfunction do not invoke Company.
consult-completion-in-regionwhich can be set as
completion-in-region-functionsuch that it handles
completion-at-point. The function works by transferring the in-buffer completion to the minibuffer. In the minibuffer, the minibuffer completion UI, for example Vertico takes over. If you prefer to perform all your completions in the minibuffer
consult-completion-in-regionis your best option.
When you observe an error in the ‘corfu--post-command’ post command hook, you should install an advice to enforce debugging. This allows you to obtain a stack trace in order to narrow down the location of the error. The reason is that post command hooks are automatically disabled (and not debugged) by Emacs. Otherwise Emacs would become unusable, given that the hooks are executed after every command.
(setq debug-on-error t) (defun force-debug (func &rest args) (condition-case e (apply func args) ((debug error) (signal (car e) (cdr e))))) (advice-add #'corfu--post-command :around #'force-debug)