tree-of-closures example for fast interpreters

gistfile1.txt

/* return a closure that computes x + y when executed */
func compile_add(x Closure, y Closure) -> Closure {
  if (x.Type == y.Type) {
    switch (x.Type) {
      case types.Int:
        /* both closures actually return an int, downcast them */
        var xe = type_cast(x, func () -> int)
        var ye = type_cast(y, func () -> int)
        /* create a closure that calls xe() and ye() and returns their sum */
        return func () -> int {
           return xe() + ye()
        }
    }
  }
  /* ... */
}