How to make yasnippet and company work nicer?

Question

In my emacs, let's say, I use a "elisp" yasnippet to extend a lisp block in org-mode. But before I extend it, company is triggered first, which gives me a menu like "1. elisp1, 2. elisp2" without an option "elisp". Now if I use tab to extend yasnippet, it is always annoying that "elisp1" always first goes on the screen. So I need to delete "1"firstly, and do the extension of yasnippet snippet.

So as a solution, I always use left arrow key to turn company completion menu off first, but the cursor now will go to "elis|p", so again I use right arrow key to move the cursor to end of "elisp|", and extend the snippet.

Here comes my question: how can I bind tab key firstly trigger yasnippet but not company to save me life?

Answer 1

This is what I created for myself, facing the same issue. It is from company-mode's Emacs Wiki page, but heavily extended:

(defun check-expansion ()
  (save-excursion
    (if (looking-at "\\_>") t
      (backward-char 1)
      (if (looking-at "\\.") t
    (backward-char 1)
    (if (looking-at "->") t nil)))))

(defun do-yas-expand ()
  (let ((yas/fallback-behavior 'return-nil))
    (yas/expand)))

(defun tab-indent-or-complete ()
  (interactive)
  (cond
   ((minibufferp)
    (minibuffer-complete))
   (t
    (indent-for-tab-command)
    (if (or (not yas/minor-mode)
        (null (do-yas-expand)))
    (if (check-expansion)
        (progn
          (company-manual-begin)
          (if (null company-candidates)
          (progn
            (company-abort)
            (indent-for-tab-command)))))))))

(defun tab-complete-or-next-field ()
  (interactive)
  (if (or (not yas/minor-mode)
      (null (do-yas-expand)))
      (if company-candidates
      (company-complete-selection)
    (if (check-expansion)
      (progn
        (company-manual-begin)
        (if (null company-candidates)
        (progn
          (company-abort)
          (yas-next-field))))
      (yas-next-field)))))

(defun expand-snippet-or-complete-selection ()
  (interactive)
  (if (or (not yas/minor-mode)
      (null (do-yas-expand))
      (company-abort))
      (company-complete-selection)))

(defun abort-company-or-yas ()
  (interactive)
  (if (null company-candidates)
      (yas-abort-snippet)
    (company-abort)))

(global-set-key [tab] 'tab-indent-or-complete)
(global-set-key (kbd "TAB") 'tab-indent-or-complete)
(global-set-key [(control return)] 'company-complete-common)

(define-key company-active-map [tab] 'expand-snippet-or-complete-selection)
(define-key company-active-map (kbd "TAB") 'expand-snippet-or-complete-selection)

(define-key yas-minor-mode-map [tab] nil)
(define-key yas-minor-mode-map (kbd "TAB") nil)

(define-key yas-keymap [tab] 'tab-complete-or-next-field)
(define-key yas-keymap (kbd "TAB") 'tab-complete-or-next-field)
(define-key yas-keymap [(control tab)] 'yas-next-field)
(define-key yas-keymap (kbd "C-g") 'abort-company-or-yas)

Basically, this makes <tab> do the right thing most of the time. Pressing tab will

• Indent the current line,
• If there is a yasnippet to expand, expand it, even if this means aborting a company completion (I don't use abbreviations much, so no abbreviation support yet),
• If a company completion is ongoing, complete with the selected item,
• Otherwise try to use company to start autocomplete,
• If there is nothing to autocomplete and we're in a yasnippet placeholder, skip to the next placeholder.

Note that if there is an opportunity to autocomplete and you are currently editing in a snippet placeholder, the situation is ambigous. As a compromise, I bound C-<tab> to skip to the next placeholder directly.

The fact that the snippet's name does not appear in the company menu and the existence of a snippet silently modifies the behaviour of the tab key is not particularly nice, unfortunately... Although at least it is possible to type <return> instead to get the completion instead of the snippet.

Answer 2

Here's the code that I'm using:

(global-set-key "\C-o" 'aya-open-line)

(defun aya-open-line ()
  "Call `open-line', unless there are abbrevs or snippets at point.
In that case expand them.  If there's a snippet expansion in progress,
move to the next field. Call `open-line' if nothing else applies."
  (interactive)
  (cond ((expand-abbrev))

        ((yas--snippets-at-point)
         (yas-next-field-or-maybe-expand))

        ((ignore-errors
           (yas-expand)))

        (t
         (open-line 1))))

aya-open-line from auto-yasnippet does more than a plain open-line:

• it tries to expand abbrevs
• it tries to move to the next field of yasnippet
• it tries to expand yasnippet
• finally, it calls open-line if all else fails