title: How to apply a function to a tuple?
body: <p>This should be an easy one.  How do I apply a function to a tuple in Scala? Viz:</p>
  
  <pre>
  scala> def f (i : Int, j : Int) = i + j
  f: (Int,Int)Int
  
  scala> val p = (3,4)
  p: (Int, Int) = (3,4)
  
  scala> f p
  :6: error: missing arguments for method f in object $iw;
  follow this method with `_' if you want to treat it as a partially applied function
         f p
         ^
  
  scala> f _ p
  :6: error: value p is not a member of (Int, Int) => Int
         f _ p
             ^
  
  scala> (f _) p
  :6: error: value p is not a member of (Int, Int) => Int
         (f _) p
               ^
  
  scala> f(p)
  :7: error: wrong number of arguments for method f: (Int,Int)Int
         f(p)
         ^
  
  scala> grr!
  </pre>
  
  <p>Many thanks in advance.</p>