title: Get available clojure namespaces
body: <p>Is there an idiomatic way to get available namespaces that can be used?</p>
  
  <p><code>(all-ns)</code> returns only already used namespaces. <code>(Package/getPackages)</code> returns all Java packages available for <code>import</code>, but only those Clojure namespaces that are already used.</p>
  
  <p>Then I stumbled upon <a href="http://learnclojure.blogspot.com/2010/02/requiring-all-possible-namespaces.html" rel="noreferrer">this post</a>, but it uses some classpath magic.</p>
  
  <p>So I want to get something like <code>('clojure.core 'clojure.set ... 'clojure.contrib.accumulators 'clojure.contrib.condition ...)</code> if I have the clojure.jar and contrib.jar on my classpath, but I haven't used anything yet.</p>