title: Property lists in LISP: are they used in real-life?
body: <p>Learning LISP I discovered that any object in LISP can have its own set of properties defined via property list. I wonder if such property lists are used in real-life LISP programming since (from my point of view) properties hide real object's structure?</p>
  
  <p>I mean I can define the list in the way:</p>
  
  <pre><code>(:property1 value1 '(10 20 30))
  </code></pre>
  
  <p>or when property list is applied it would like just as:</p>
  
  <pre><code>('(10 20 30))
  </code></pre>
  
  <p>And no one will no idea that this list has hidden any property.</p>
  
  <p>So when a property list should be used?</p>