code: func (f *Frame) First() (noder.Noder, bool) {
  	if f.Len() == 0 {
  		return nil, false
  	}
  
  	top := f.Len() - 1
  
  	return f.stack[top], true
  }
docs: // First returns, but dont extract, the noder with the alphabetically
  // smaller name in the frame and true if the frame was not empy.
  // Otherwise it returns nil and false.