尝试一个简单的解析器组合器,我遇到了编译错误。
我想将“Smith, Joe”解析为它的 Name 对象,例如 Name(Joe, Smith)。很简单,我猜。
这是与此相关的代码:
import util.parsing.combinator._
class NameParser extends JavaTokenParsers {
lazy val name: Parser[Name] =
lastName <~ "," ~> firstName ^^ {case (l ~ f) => Name(f, l)}
lazy val lastName = stringLiteral
lazy val firstName = stringLiteral
}
case class Name(firstName:String, lastName: String)
我正在通过
object NameParserTest {
def main(args: Array[String]) {
val parser = new NameParser()
println(parser.parseAll(parser.name, "Schmo, Joe"))
}
}
出现编译错误:
error: constructor cannot be instantiated to expected type;
found : NameParser.this.~[a,b]
required: java.lang.String
lazy val name: Parser[Name] = lastName <~ "," ~> firstName ^^ {case (l ~ f) => Name(f, l)}
我在这里想念什么?