scala - 字符串插值转义引号 PITA

Question

让我抓狂的是，字符串插值有一些特殊的规则，不允许从 a + b 直接翻译。风格:

// ok
def test(f: java.io.File) = {
  val abs = f.getAbsoluteFile
  val isF = abs.isFile
  "select " + (if (isF) "file" else "folder") +"\"" + abs.getName +"\" of folder"
}

// fail
def test(f: java.io.File) = {
  val abs = f.getAbsoluteFile
  val isF = abs.isFile
  s"select ${if (isF) "file" else "folder"} \"${abs.getName}\" of folder"
}

然后是一个可爱的错误消息:

<console>:38: error: value $ is not a member of String
         s"select ${if (isF) "file" else "folder"} \"${abs.getName}\" of folder of the front window"
                                                     ^

这里的s字符串有什么问题？

Answer 1

问题是您不能在单引号字符串中保留未转义的引号，就像在单词文件和文件夹周围放置引号时所做的那样。尝试使用三重引号字符串，它允许在其中包含未转义的引号(它仅以第二个三引号结尾):

s"""select ${if (isF) "file" else "folder"} "${abs.getName}" of folder"""