访问Scala 3.0中的注释值

import scala.annotation.StaticAnnotation

class MyAnnotation(val value: String) extends StaticAnnotation

@MyAnnotation("Hello, Scala!")
class MyClass {
  // ...
}

import scala.reflect.runtime.universe._
import scala.reflect.runtime.{currentMirror => cm}

object AnnotationExample {
  def main(args: Array[String]): Unit = {
    val sym = typeOf[MyClass].typeSymbol.asClass
    val ann = sym.primaryConstructor.asMethod.annotations.find(_.tree.tpe =:= typeOf[MyAnnotation])
    ann.foreach { a =>
      val instanceMirror = cm.reflect(a.tree.children.tail.head.asInstanceOf[ValDef].rhs)
      val value = instanceMirror.reflectMethod(a.tree.children.head.asInstanceOf[DefDef].symbol)(())
      println(s"Annotation value: $value")
    }
  }
}