code: public Object resumeGenerator(Context cx, Scriptable scope,
                                    int operation, Object state, Object value)
      {
          throw new EvaluatorException("resumeGenerator() not implemented");
      }
docs: Resume execution of a suspended generator.
  @param cx The current context
  @param scope Scope for the parent generator function
  @param operation The resumption operation (next, send, etc.. )
  @param state The generator state (has locals, stack, etc.)
  @param value The return value of yield (if required).
  @return The next yielded value (if any)