using-auto-completion-in-emacs.org

• Completion with company or auto-complete
• Frequency-based suggestions via company-statistics
• Integration with yasnippets

You can customize the user experience of auto-completion with the following layer variables:

1. auto-completion-return-key-behavior set the action to perform when the RET key is pressed, the possible values are:

   • complete completes with the current selection
   • nil does nothing

2. auto-completion-tab-key-behavior set the action to perform when the TAB key is pressed, the possible values are:

   • complete completes with the current selection
   • cycle completes the common prefix and cycle between candidates
   • nil does nothing
3. auto-completion-complete-with-key-sequence is a string of two characters denoting a key sequence that will perform a complete action if the sequence as been entered quickly enough. If its value is nil then the feature is disabled.
4. auto-completion-complete-with-key-sequence-delay is the number of seconds to wait for the auto-completion key sequence to be entered. The default value is 0.1 seconds.
5. auto-completion-idle-delay is the number of seconds to wait before suggesting completions. The default value is 0.2 seconds.

The default configuration of the layer is:

(setq-default dotspacemacs-configuration-layers '(
  (auto-completion :variables
                   auto-completion-return-key-behavior 'complete
                   auto-completion-tab-key-behavior 'cycle
                   auto-completion-complete-with-key-sequence nil
                   auto-completion-complete-with-key-sequence-delay 0.1
                   auto-completion-idle-delay 0.2
                   auto-completion-private-snippets-directory nil)
                   ))

jk is a good candidate for auto-completion-complete-with-key-sequence if you don't use it already.

The following directories are added by default:

• ~/.emacs.d/elpa/yasnippet-xxxxx/snippets
• ~/.emacs.d/layers/auto-completion/snippets
• ~/.emacs.d/private/snippets (conditional to the value of auto-completion-private-snippets-directory)
• ~/.spacemacs.d/snippets (conditional to the existence of ~/.spacemacs.d directory)

You can provide additional directories by setting the variable auto-completion-private-snippets-directory which can take a string in case of a single path or a list of paths. If its value is nil then the path ~/.emacs.d/private/snippets is used.

By default, snippets are not shown in the auto-completion popup. To show them in the popup, set the variable auto-completion-enable-snippets-in-popup to t.

  (setq-default dotspacemacs-configuration-layers
                '((auto-completion :variables
                                   auto-completion-enable-snippets-in-popup t)))

To enable automatic docstring tooltips set auto-completion-enable-help-tooltip to t.

(setq-default dotspacemacs-configuration-layers
  '((auto-completion :variables
                    auto-completion-enable-help-tooltip t)))

To enable manual non-automatic invocation of docstring tooltips, set it to manual. The tooltip can be invoked manually by pressing M-h.

(setq-default dotspacemacs-configuration-layers
  '((auto-completion :variables
                    auto-completion-enable-help-tooltip 'manual)))

To enable sorting auto-completion results by their usage frequency set auto-completion-enable-sort-by-usage to t. This feature is provided by the company-statistics package when company is used. The variable has no effect when auto-complete is used.

(setq-default dotspacemacs-configuration-layers
  '((auto-completion :variables
                    auto-completion-enable-sort-by-usage t)))

By default Spacemacs enables auto-completion explicitly for each supported major-mode, it means that company and auto-complete are not enabled globally, it allows more flexibility to choose an auto-completion engine for a given mode.

You may want to enable company globally to get auto-completion everywhere even in the modes which are not configured by Spacemacs. To do so, you just have to add (global-company-mode) in the dotspacemacs/user-config function of your dotfile.

Note that if you want to enable auto-complete globally you will have to disable company first, see the next section to do so.

You can disable company by adding it to the dotspacemacs-excluded-packages variable, then you are free to enable auto-complete globally.

Here is an example to add company auto-completion to python buffers via the package company-anaconda.

In the file packages.el of the python layer:

  ;; Add the relevant packages to the layer
  ;; here it is `company-anaconda'
  (setq python-packages
    '(...
      (company-anaconda :toggle (configuration-layer/package-used-p 'company))
      ...))

  (defun python/init-company-anaconda ()
    (use-package company-anaconda
      :defer t
      :init
      (spacemacs|add-company-backends
         :backends company-anaconda
         :modes python-mode)))

Many spacemacs layers (e.g., python, html, haskell) configure company mode backends to provide mode-specific completion. These modes will include completion backends specified in the `spacemacs-default-company-backends` variable. The defaults should work well, but you can configure this variable in your .spacemacs file with (e.g.)

  (setq-default
   dotspacemacs-configuration-layers
   '((auto-completion :variables
                      spacemacs-default-company-backends '(company-files company-capf))))

For nicer-looking faces, try adding the following to `custom-set-faces` in your dotspacemacs file.

(custom-set-faces
 '(company-tooltip-common
   ((t (:inherit company-tooltip :weight bold :underline nil))))
 '(company-tooltip-common-selection
   ((t (:inherit company-tooltip-selection :weight bold :underline nil)))))

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