Frequently Asked Questions

If there is a newline at the end of a snippet definition file, YASnippet will add a newline when expanding that snippet. When editing or saving a snippet file, please be careful not to accidentally add a terminal newline.

Note that some editors will automatically add a newline for you. In Emacs, if you set require-final-newline to t, it will add the final newline automatically.

First check the mode line to see if there's yas. If not, then try M-x yas-minor-mode to manually turn on the minor mode and try to expand the snippet again. If it works, then, you can add the following code to your .emacs before loading YASnippet:

(add-hook 'the-major-mode-hook 'yas-minor-mode-on)

where the-major-mode is the major mode in which yas-minor-mode isn't enabled by default.

The command M-x yas-global-mode turns YASnippet on automatically for all major modes.

If yas-minor-mode is on but the snippet still not expanded. Then try to see what command is bound to the TAB key: press C-h k and then press TAB. Emacs will show you the result.

You'll see a buffer prompted by Emacs saying that TAB runs the command .... Alternatively, you might see <tab> runs the command ..., note the difference between TAB and <tab> where the latter has priority. If you see <tab> bound to a command other than yas-expand, (e.g. in org-mode) you can try the following code to work around:

(add-hook 'org-mode-hook
	  (let ((original-command (lookup-key org-mode-map [tab])))
	    `(lambda ()
	       (setq yas-fallback-behavior
		     '(apply ,original-command))
	       (local-set-key [tab] 'yas-expand))))

replace org-mode-hook and org-mode-map with the major mode hook you are dealing with (Use C-h m to see what major mode you are in).

As an alternative, you can also try

(defun yas-advise-indent-function (function-symbol)
  (eval `(defadvice ,function-symbol (around yas-try-expand-first activate)
	   ,(format
	     "Try to expand a snippet before point, then call `%s' as usual"
	     function-symbol)
	   (let ((yas-fallback-behavior nil))
	     (unless (and (interactive-p)
			  (yas-expand))
	       ad-do-it)))))

(yas-advise-indent-function 'ruby-indent-line)

To advise the modes indentation function bound to TAB, (in this case ruby-indent-line) to first try to run yas-expand.

If the output of C-h k RET <tab> tells you that <tab> is indeed bound to yas-expand but YASnippet still doesn't work, check your configuration and you may also ask for help on the discussion group. See this particular thread for quite some solutions and alternatives.

Don't forget to attach the information on what command is bound to TAB as well as the mode information (Can be obtained by C-h m).

A workaround is to inhibit flyspell overlays while the snippet is active:

(add-hook 'flyspell-incorrect-hook
	  #'(lambda (dummy1 dummy2 dymmy3)
	      (and yas-active-field-overlay
		   (overlay-buffer yas-active-field-overlay))))

This is apparently related to overlay priorities. For some reason, the keymap property of flyspell's overlays always takes priority over the same property in YASnippet's overlays, even if one sets the latter's priority property to something big. If you know emacs-lisp and can solve this problem, drop a line in the discussion group.

Edit the keymaps yas-minor-mode-map and yas-keymap as you would any other keymap:

(define-key yas-minor-mode-map (kbd "<tab>") nil)
(define-key yas-minor-mode-map (kbd "TAB") nil)
(define-key yas-minor-mode-map (kbd "<the new key>") 'yas-expand)

;;keys for navigation
(define-key yas-keymap [(tab)]       nil)
(define-key yas-keymap (kbd "TAB")   nil)
(define-key yas-keymap [(shift tab)] nil)
(define-key yas-keymap [backtab]     nil)
(define-key yas-keymap (kbd "<new-next-field-key>") 'yas-next-field-or-maybe-expand)
(define-key yas-keymap (kbd "<new-prev-field-key>") 'yas-prev)

The best way, since version 0.6.1c, is to set the default value of the variable yas-dont-activate to a lambda function like so:

(set-default 'yas-dont-activate
	     #'(lambda ()
		 (and yas-root-directory
		      (null (yas-get-snippet-tables)))))

This is also the default value starting for that version. It skips the minor mode in buffers where it is not applicable (no snippet tables), but only once you have setup your yas-root-directory.

• Note: This question applies if you're still defining snippets whose key is the filename. This is behavior still provided by version 0.6 for backward compatibilty, but is somewhat deprecated…

For example, you want to define a snippet by the key < which is not a valid character for filename on Windows. This means you can't use the filename as a trigger key in this case.

You should rather use the # key: directive to specify the key of the defined snippet explicitly and name your snippet with an arbitrary valid filename, lt.YASnippet for example, using < for the # key: directive:

# key: <
# name: <...></...>
# --
<${1:div}>$0</$1>