Scala 吸血鬼方法、类型提供程序宏和缺少runtime.VolatileObjectRef
我正在尝试编写一个类型提供程序宏,它使用所描述的吸血鬼方法技巧;这是我的实现的一个最小模型:Scala 吸血鬼方法、类型提供程序宏和缺少runtime.VolatileObjectRef,scala,scala-macros,scala-macro-paradise,Scala,Scala Macros,Scala Macro Paradise,我正在尝试编写一个类型提供程序宏,它使用所描述的吸血鬼方法技巧;这是我的实现的一个最小模型: object DeriveFamily { def minimal: Any = macro DeriveFamilyMacros.minimal } object DeriveFamilyMacros { class body(tree: Any) extends StaticAnnotation def bodyImpl(c: Context) = { import c.un
object DeriveFamily {
def minimal: Any = macro DeriveFamilyMacros.minimal
}
object DeriveFamilyMacros {
class body(tree: Any) extends StaticAnnotation
def bodyImpl(c: Context) = {
import c.universe._
val field = c.macroApplication.symbol
val bodyAnn = field.annotations.filter(_.tree.tpe <:< typeOf[body]).head
bodyAnn.tree.children.tail.head
}
def minimal(c: Context): c.Tree = {
import c.universe._
q"""object Foobar { val _x = "X"; @DeriveFamilyMacros.body(Foobar._x) def x: String = macro DeriveFamilyMacros.bodyImpl }; Foobar"""
}
}
非常欢迎您提供任何帮助,谢谢。我对宏不太熟悉,但我记得看到过类似的东西。在
minimal
中使用类而不是对象不是解决了这个问题吗?
object Working {
def x = {
val foobar = DeriveFamily.minimal
println(foobar.x)
}
x // Prints "X"
}
object NotWorking {
val foobar = DeriveFamily.minimal
println(foobar.x)
/*
[trace] Stack trace suppressed: run last common/test:compileIncremental for the full output.
[error] (common/test:compileIncremental) java.lang.IllegalArgumentException: Could not find proxy for var Foobar$module: runtime.VolatileObjectRef in List(variable Foobar$module, value foobar, Object NotWorking, package <root>) (currentOwner= value <local NotWorking> )
*/
}