title: Use functional combinators on Scala Tuples?
body: <p>'map' preserves the number of elements, so using it on a Tuple seems sensible.</p>
  
  <p>My attempts so far:</p>
  
  <pre><code>scala&gt; (3,4).map(_*2)    
  error: value map is not a member of (Int, Int)
         (3,4).map(_*2)
               ^
  scala&gt; (3,4).productIterator.map(_*2)
  error: value * is not a member of Any
         (3,4).productIterator.map(_*2)
                                    ^
  scala&gt; (3,4).productIterator.map(_.asInstanceOf[Int]*2)
  res4: Iterator[Int] = non-empty iterator
  
  scala&gt; (3,4).productIterator.map(_.asInstanceOf[Int]*2).toList
  res5: List[Int] = List(6, 8)
  </code></pre>
  
  <p>It looks quite painful... And I haven't even begun to try to convert it back to a tuple.<br>
  Am I doing it wrong? Could the library be improved?</p>