title: keyword symbol enclosed by two pipes
body: <p>Suppose a function <code>fun</code> in the code below, my goal is evaluating <code>expr2</code> below. </p>
  
  <pre><code>(defun fun (&amp;key (x nil)) x)
  (defparameter expr1 (list 'fun :x 2))
  (defparameter expr2 (list 'fun (intern "x" "KEYWORD") 2))
  </code></pre>
  
  <p>As expected, <code>(eval expr1)</code> gives <code>2</code>, but <code>(eval expr2)</code> gives an error like </p>
  
  <blockquote>
    <p>*** - FUN: illegal keyword/value pair :|x|, 2 in argument list.
          The allowed keywords are (:X) The following restarts are available: ABORT          :R1      Abort main loop</p>
  </blockquote>
  
  <p>Why does this error occurs? and How can I fix it?</p>