yasnippet/doc/faq.org

#+SETUPFILE: org-setup.inc

#+TITLE: Frequently Asked Questions

* Why is there an extra newline?

If you have a newline at the end of the snippet definition file, then
YASnippet will add a newline when you expanding a snippet. Please don't
add a newline at the end if you don't want it when you saving the
snippet file.

Note 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
for you automatically.

* Why doesn't TAB expand a snippet?

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:

#+BEGIN_SRC emacs-lisp
  (add-hook 'the-major-mode-hook 'yas-minor-mode-on)
#+END_SRC

where =the-major-mode= is the major mode in which [[sym:yas-minor-mode][=yas-minor-mode=]] isn't
enabled by default.

From YASnippet 0.6 you can also use the command =M-x yas-global-mode= to
turn on YASnippet automatically for /all/ major modes.

If [[sym:yas-minor-mode][=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 [[sym:yas-expand][=yas-expand=]], (e.g. in =org-mode=) you can try the
following code to work around:

#+BEGIN_SRC emacs-lisp
  (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))))
#+END_SRC

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

#+BEGIN_SRC emacs-lisp
  (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)
#+END_SRC

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

If the output of =C-h k RET <tab>= tells you that =<tab>= is indeed
bound to [[sym:yas-expand][=yas-expand=]] but YASnippet still doesn't work, check your
configuration and you may also ask for help on the [[http://groups.google.com/group/smart-snippet][discussion group]].
See this particular [[http://code.google.com/p/yasnippet/issues/detail?id=93&can=1][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=).

* Why doesn't TAB navigation work with flyspell

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

#+BEGIN_SRC emacs-lisp
  (add-hook 'flyspell-incorrect-hook
            #'(lambda (dummy1 dummy2 dymmy3)
                (and yas-active-field-overlay
                     (overlay-buffer yas-active-field-overlay))))
#+END_SRC

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
[[http://groups.google.com/group/smart-snippet][discussion group]].

* How to I use alternative keys, i.e. not TAB?

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

#+begin_src emacs-lisp :exports code
   (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)
#+end_src

* How do I turn off the minor mode where in some buffers?

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

#+BEGIN_SRC emacs-lisp
  (set-default 'yas-dont-activate
               #'(lambda ()
                   (and yas-root-directory
                        (null (yas-get-snippet-tables)))))
#+END_SRC

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.

* How do I define an abbrev key containing characters not supported by
the filesystem?

-  *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:

#+BEGIN_SRC snippet
  # key: <
  # name: <...></...>
  # --
  <${1:div}>$0</$1>
#+END_SRC