title: How to make the yasnippet as the auto-complete backend?
body: <p>I want to make the <code>yasnippet</code> as the backend of the <code>auto-complete</code>. However, it doesn't work. what I do after searched the internet is as follows:
  get the <a href="http://www.cx4a.org/pub/auto-complete-yasnippet.el" rel="nofollow">auto-complete-yasnippet.el</a>, add some elisp in the <code>.emacs</code> like this:</p>
  
  <pre><code>(add-to-list 'load-path
       "~/.emacs.d/plugins/yasnippet")
  (require 'yasnippet)
  (yas-global-mode 1)
  (yas-minor-mode nil)
  (global-set-key (kbd "M-/") 'yas/expand)
  
  ;; Auto-complete settings
  ;; this is the code for the auto-complete
  (require 'auto-complete-config)
  (add-to-list 'ac-dictionary-directories "~/.emacs.d//ac-dict")
  (ac-config-default)
  
  ;;setup for auto-complete-yasnippet
  (require 'auto-complete-yasnippet)
  (setq-default ac-sources
        '(
          ;; ac-source-semantic
          ac-source-yasnippet
          ac-source-abbrev
          ac-source-words-in-buffer
          ac-source-words-in-all-buffer
          ;; ac-source-imenu
          ac-source-files-in-current-dir
          ac-source-filename
          )
        )
  </code></pre>
  
  <p>I look at the content in the <code>ac-sources</code> in *scratch* with <kbd>C-h v</kbd>, and it does have the <code>ac-source-yasnippet</code>. someone <a href="http://www.emacswiki.org/emacs/AutoComplete" rel="nofollow">said</a> that there may be something wrong with the version and upgrade of <code>auto-complete</code> as well as <code>yasnippet</code>. How can it be fixed? 
  My <code>emacs</code> version is 23.3.1 my <code>auto-complete</code> version is 1.3.1 and my <code>yasnippet</code> version is 0.8.0(beta) which is just downloaded from the <a href="https://github.com/capitaomorte/yasnippet" rel="nofollow">github</a>. any help?</p>