Company

Company comes with a ‘company-capf’ backend that uses the completion-at-point functions, which in turn use completion styles. This means that the ‘company-capf’ backend will automatically use ‘orderless’, no configuration necessary!

But there are a couple of points of discomfort:

1. Pressing SPC takes you out of completion, so with the default separator you are limited to one component, which is no fun. To fix this add a separator that is allowed to occur in identifiers, for example, for Emacs Lisp code you could use an ampersand:

   (setq orderless-component-separator "[ &]")

2. The matching portions of candidates aren’t highlighted. That’s because ‘company-capf’ is hard-coded to look for the ‘completions-common-part’ face, and it only use one face, ‘company-echo-common’ to highlight candidates.

   So, while you can’t get different faces for different components, you can at least get the matches highlighted in the sole available face with this configuration:

   (defun just-one-face (fn &rest args)
     (let ((orderless-match-faces [completions-common-part]))
       (apply fn args)))
   
   (advice-add 'company-capf--candidates :around #'just-one-face)

   (Aren’t dynamically scoped variables and the advice system nifty?)

If you would like to use different ‘completion-styles’ with ‘company-capf’ instead, you can add this to your configuration:

;; We follow a suggestion by company maintainer u/hvis:
;; https://www.reddit.com/r/emacs/comments/nichkl/comment/gz1jr3s/
(defun company-completion-styles (capf-fn &rest args)
  (let ((completion-styles '(basic partial-completion)))
    (apply capf-fn args))

(advice-add 'company-capf :around #'company-completion-styles)