code: func (g *Graph) simplify() {
  
  	if g == nil {
  		return
  	}
  
  	for _, node := range g.Out {
  		if TypePath == node.ThisString() {
  			s := node.GetAt(0).ThisString()
  
  			switch s {
  			case "if":
  				node.This = TypeIf
  				node.DeleteAt(0)
  			case "end":
  				node.This = TypeEnd
  				node.DeleteAt(0)
  			case "else":
  				node.This = TypeElse
  				node.DeleteAt(0)
  			case "for":
  				node.This = TypeFor
  				node.DeleteAt(0)
  			case "break":
  				node.This = TypeBreak
  				node.DeleteAt(0)
  			}
  		}
  	}
  
  }
docs: // simplify converts !p TYPE in !TYPE for keywords if, end, else, for and break.