I rather like how Go decided to handle this, using "type switches": switch x := node.(type) { case Node: // x is of type Node in this block cas

I rather like how Go decided to handle this, using "type switches": switch x := node.(type) { case Node: // x is of type Node in this block case Leaf: // x is of type Leaf in this block } (http://golang.org/doc/go_spec.html#Type_switches http://golang.org/doc/go_spec.html#Type_switches)