title: How to change smart assign key ("_" to "<-") binding in ESS
body: <p>In emacs ESS, how do I correctly change the keybinding for ess-smart-S-assign?</p>
  
  <p>What I tried is adding</p>
  
  <pre><code>(custom-set-variables
      '(ess-smart-S-assign-key ":"))
  </code></pre>
  
  <p>to my <code>.emacs</code>, but that made weird things happen: When I press <code>:</code>, just a normal <code>:</code> appears. On the other hand, pressing <code>_</code> once yields <code>&lt;-</code> as usual, whereas pressing <code>_</code> a second time then converts this to <code>:</code>.
  The desired behavior would be to be able to use <code>_</code> as a normal key, with <code>:</code> being converted to <code>&lt;-</code>.</p>
  
  <p>I am using the official emacs 24.3 for windows and the latest development version of ESS (14.06).</p>