title: Getting the current directory in Emacs Lisp
body: <p>I am trying to write a .dir-locals.el file. I want to dynamically find the directory that the file is in and concatenate it with "TAGS". This was my first try:</p>
  
  <pre><code>((nil . ((tags-file-name . (concat default-directory "TAGS")))))
  </code></pre>
  
  <p>This doesn't work. I am not an Emacs Lisp expert. What is wrong with it?</p>