title: Convert special characters like ' \t ' to " \t " (a real tab)
body: <p>I want to make a CSV file importer on my website. I want the user to choose the delimiter.</p>
  
  <p>The problem is when the form submits, the delimiter field is stored as '\t', for example, so when I'm parsing the file, I search for the string '\t' instead of a real TAB. It does the same thing with every special characters like \r, \n, etc...</p>
  
  <p>I want to know the way or the function to use to convert these characters to their true representation without using an array like:</p>
  
  <ul>
  <li>'t' => "\t"</li>
  <li>'r' => "\r"</li>
  <li>...</li>
  </ul>