#+TITLE: Ivy layer

#+TAGS: completion|layer

* Table of Contents                     :TOC_5_gh:noexport:
- [[#description][Description]]
  - [[#features][Features:]]
- [[#install][Install]]
- [[#configuration][Configuration]]
  - [[#general][General]]
  - [[#advanced-buffer-information][Advanced buffer information]]
- [[#key-bindings][Key bindings]]
  - [[#transient-state][Transient state]]

* Description
This layer enables Ivy for completion. It will replace the default completion by
[[https://github.com/emacs-helm/helm][Helm]].

These completion systems are the central control towers of Spacemacs, they are
used to manage buffers, projects, search results, configuration layers, toggles
and more...

Mastering your choice of completion system will make you a Spacemacs power user.

** Features:
- Project wide =grep= like text search via =search-auto=
- Project wide text replacements using =counsel-imenu=
- Buffer wide dynamic text search via =swiper=
- Detailed configuration parameters for ivy appearance
- Intuitive =transient state=
- Advanced buffer information with =ivy-rich=

* Install
To use this configuration layer, add it to your =~/.spacemacs=. You will need to
add =ivy= to the existing =dotspacemacs-configuration-layers= list in this
file.

* Configuration
** General
You can customize ivy with the following variables:
- =ivy-wrap= Whether C-n and C-p should wrap-around when at the first or
  last candidate. The default value is =nil=.
- =ivy-extra-directories= Setting this to =nil= hides . and .. directories from
  file name completion. You can still go up a directory up by ~DEL~.
  The default value is ("../", "./").
- =ivy-use-virtual-buffers= Add bookmarks and recent files to buffer completion
  menu. The Spacemacs default is t.
- =ivy-height= The height of the minibuffer. The Spacemacs default is 15.
- =ivy-use-selectable-prompt= When non-nil, make the prompt line selectable like
  a candidate. The Spacemacs default value is =t=.
- =ivy-re-builders-alist= An alist of regex building functions for each
  collection function. See ivy documentation for possible choices. Use
  =spacemacs/ivy--regex-plus= instead of =ivy--regex-plus= to get correct
  highlighting in the search results of =spacemacs/search-project-auto= and
  similar search commands provided by Spacemacs.
- =ivy-ret-visits-directory= Whether ~RET~ and ~C-j~ should be swapped in ivy
  minibuffer so ~RET~ acts like Ido and descends into directory. It is described
  [[https://github.com/abo-abo/swiper/wiki/ido-style-folder-navigation][here]] (probably outdated). Default value is =nil=.

** Advanced buffer information
To display more information about buffers set the layer variable
=ivy-enable-advanced-buffer-information= to =t= which will enable =ivy-rich=.

Note that =ivy-rich= has been reported to be very slow on =macOS=. This feature
is disabled by default.

#+BEGIN_SRC emacs-lisp
  (setq-default dotspacemacs-configuration-layers '(
    (ivy :variables ivy-enable-advanced-buffer-information t)))
#+END_SRC

* Key bindings
If you choose =ivy= as completion system, make sure to read the [[http://oremacs.com/swiper/][official manual]].
In case you don't want to read everything, at least familiarise with
[[http://oremacs.com/swiper/#minibuffer-key-bindings][minibuffer key bindings]].

Some useful key bindings are presented in the following table.

| Key binding | Description                                                                                          |
|-------------+------------------------------------------------------------------------------------------------------|
| ~RET~       | call default action on current candidate                                                             |
| ~M-RET~     | the same as ~RET~ but doesn't close completion minibuffer                                            |
| ~C-M-j~     | use current input immediately (this can be used to create a new file in Find File)                   |
| ~tab~       | complete partially                                                                                   |
| ~M-o~       | show the list of valid actions on current candidate (then press any of described keys to execute it) |
| ~C-M-o~     | the same as ~M-o~ but doesn't close completion minibuffer                                            |
| ~C-'~       | use avy to quickly select completion on current page (sometimes faster than using arrows)            |
| ~<ESC>~     | close minibuffer                                                                                     |

** Transient state
Press ~M-SPC~ anytime in Ivy to get into the transient state.

| Key binding | Description                                             |
|-------------+---------------------------------------------------------|
| ~j~         | select next candidate                                   |
| ~k~         | select previous candidate                               |
| ~d~         | call default action on candidate                        |
| ~g~         | the same as ~d~ but doesn't close completion minibuffer |
| ~o~         | leave transient state                                   |