title: How can I determine number of arguments to a function in Clojure?
body: <p>Given a function x in clojure how can I programatically get a count of the number of arguments?</p>
  
  <p>eg:</p>
  
  <pre><code>(fn a [b c] ...) has has two arguments
  (fn a [] ...) has has zero arguments
  </code></pre>