title: ANT element in csv matching
body: <p>I need to write a regex to match an element in a comma-separated list, ignoring whitespaces near <code>,</code>.
  For example:
  <code>elem1, elem2  ,elem3,  elem4  ,elem5 ,elem6</code>  </p>
  
  <p>Any of: <code>elem1</code> <code>elem2</code> <code>elem3</code> <code>elem4</code> <code>elem5</code> <code>elem6</code> should match.</p>
  
  <p>The trailing comma (before end of line) is not allowed.</p>
  
  <p>I tried this pattern:<br>
  <code>pattern="(^|/,)\s*@{value}\s*(/,|$)"</code><br>
  but it doesn't work. (False negative)</p>
  
  <p>How can i do that pattern? What's wrong in mine?</p>
  
  <p>Thanks.</p>