code: func (v *printVisitor) VisitString(node *StringLiteral) interface{} {
  	if v.original {
  		v.str(node.Value)
  	} else {
  		v.str("\"" + node.Value + "\"")
  	}
  
  	return nil
  }
docs: // Literals
  // VisitString implements corresponding Visitor interface method