如何使用 Scala XML 返回一个空的 NodeSeq? [英] How to return an Empty NodeSeq using Scala XML?

问题描述

我正在使用不同的函数构建一个 XML，例如以下示例:

I'm building an XML by pieces using different functions such as the following example:

<xml>
  { maybeXml(param) }
</xml>

并尝试根据参数的值返回一个空或非空的 NodeSeq，例如:

And trying to return an Empty or Non-empty NodeSeq based on the value of the param such as:

def maybeXml(param: Boolean): NodeSeq = {
  if(param) <someXml></someXml>
  else ??? //Empty or None doesn't work
}

我现在使用的解决方案只是将函数类型定义为 Option[NodeSeq]，然后将其用作 mayXml.getOrElse("")，但这对我来说没有多大意义.我目前的使用情况如下:

The solution I'm using now is just defining the function type as Option[NodeSeq] and then using it as maybeXml.getOrElse(""), but that doesn't make that much sense to me. My current usage is as follows:

<xml>
  { maybeXml(param).getOrElse("") }
</xml>

def maybeXml(param: Boolean): NodeSeq = {
  if(param) Some(<someXml></someXml>)
  else None
}

直接使用 Empty NodeSeq 是否有更好的表达方式?

Is a better way to express this using an Empty NodeSeq directly?

推荐答案

对于空 NodeSeq 使用 NodeSeq.Empty

def maybeXml(param: Boolean): NodeSeq = {
  if(param) <someXml></someXml>
  else NodeSeq.Empty
} 

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