title: What are Context-Free Grammars and Backus Naur Form?
body: <p>Can someone please explain in layman's terms:</p>
  
  <ol>
  <li><p>what a context-free grammar is?</p></li>
  <li><p>what Backus Naur Form is?</p></li>
  <li><p>How to use this notation?</p></li>
  <li><p>How to do string derivation?</p></li>
  <li><p>How to describe language syntax?</p></li>
  </ol>