Question

我正在编写正则表达式以从下面的句子中提取令牌，例如“（”是LEFT_BRACKET，“是”是IS，“teddy”是属性（TEDDY，INT），“或”是“OR”，“ NULL“为NULL，”）“是RIGHT_BRACKET。但不知何故，最后一个单词NULL将作为属性（NULL）而不是单独的标记NULL。如果我在NULL之后给出空格，那么只有它作为标记，否则它与属性匹配。请帮助解决此问题。

 **Sentence is**   (data is teddy or is NULL)

    **The corresponding regex is as follows:**

     <b>1. regex to resolve ")"</b>
 case class LEFT_BRACKET() extends Token {
      override def pattern: Parser[Token] = regex("\\(".r) ^^ (_ => LEFT_BRACKET)
    }
     <b>2. regex to resolve "is"</b> 
 case class IS() extends Token {
      override def pattern: Parser[Token] = regex("(?i)^is ".r) ^^ (_ => IS)
    }
     <b>3. regex to resolve "teddy"</b>   
    def attrR = regex("[\\{\\{]*[a-zA-Z_][a-zA-Z0-9_.}}]*[\\}\\}]*".r)
    def attribute: Parser[ATTRIBUTE] = (attrR) ^^ (attr => {
    val dTYPE: TYPE = TYPE.STRING
    ATTRIBUTE(attr, dTYPE)
  })
      <b>4. regex to resolve "or"</b>  
 case class OR() extends Token {
      override def pattern: Parser[Token] = regex("(?i)^is ".r) ^^ (_ => OR)
    }
       <b>5. regex to resolve "null"</b> 
 case class NULL() extends Token {
      override def pattern: Parser[Token] = regex("(?i)^null ".r) ^^ (_ => NULL)
    }

**Above case classes are being called with the help of object.**

RegEx-Scala（在匹配模式以分离令牌时面临问题）

0 个答案: