title: Ant - String contains within an array of String
body: <p>I am basically trying to do the following thing in Ant (v1.9.4):</p>
  
  <p>I have a list of fixed string like {a,b,c,d} --> First how should I declare this in Ant?
  Then I have an input parameter such as ${mystring} and I want to check if the variable value is in my list. Which means in this example, if the variable value is equals to a or b or c or d.
  If so return true else false (or 0 and 1 something like that).</p>
  
  <p>Is there a simple way to do that?</p>
  
  <p>Thanks,</p>
  
  <p>Thiago</p>