sbt - 使用宏天堂并与 2.12/2.13 交叉编译

Question

从 Scala 2.13 开始，macro-paradise已内联在编译器中，可通过编译器标志获得:

Compile / scalacOptions += "-Ymacro-annotations"

作为引用，在以前的 Scala 版本中，macro-paradise 可通过编译器插件获得:

addCompilerPlugin("org.scalamacros" % "paradise" % "2.1.1" cross CrossVersion.full)

在针对 Scala 2.12 和 2.13 的构建中，根据 Scala 版本的值，有条件地添加第一个设置或第二个设置的规范方法是什么？

我想写以下内容，但不起作用:

CrossVersion.partialVersion(scalaVersion.value) match {
  case Some((2, n)) if n >= 13 => Compile / scalacOptions += "-Ymacro-annotations"
  case _ => addCompilerPlugin("org.scalamacros" % "paradise" % "2.1.1" cross CrossVersion.full)
}

它失败并出现以下错误:

error: `value` can only be used within a task or setting macro, such as :=, +=, ++=, Def.task, or Def.setting.
      CrossVersion.partialVersion(scalaVersion.value) match {
                                               ^

同时，我可以使用以下解决方法，但我希望支持更简单的解决方案:

Compile / scalacOptions ++= {
  CrossVersion.partialVersion(scalaVersion.value) match {
    case Some((2, n)) if n >= 13 => "-Ymacro-annotations" :: Nil
    case _ => Nil
  }
}

libraryDependencies ++= {
  CrossVersion.partialVersion(scalaVersion.value) match {
    case Some((2, n)) if n >= 13 => Nil
    case _ => compilerPlugin("org.scalamacros" % "paradise" % "2.1.1" cross CrossVersion.full) :: Nil
  }
}

Answer 1

如果你想写

CrossVersion.partialVersion(scalaVersion.value) match {
  case Some((2, n)) if n >= 13 => Compile / scalacOptions += "-Ymacro-annotations"
  case _ => addCompilerPlugin("org.scalamacros" % "paradise" % "2.1.1" cross CrossVersion.full)
}

一种选择是定义 SBT custom command像这样

def compileWithMacroParadise: Command = Command.command("compileWithMacroParadise") { state =>
  import Project._
  val extractedState = extract(state)
  val stateWithMacroParadise = CrossVersion.partialVersion(extractedState.get(scalaVersion)) match {
    case Some((2, n)) if n >= 13 => extractedState.appendWithSession(Seq(Compile / scalacOptions += "-Ymacro-annotations"), state)
    case _ => extractedState.appendWithSession(addCompilerPlugin("org.scalamacros" % "paradise" % "2.1.1" cross CrossVersion.full), state)
  }
  val (stateAfterCompileWithMacroParadise, _) = extract(stateWithMacroParadise).runTask(Compile / compile, stateWithMacroParadise)
  stateAfterCompileWithMacroParadise
}

commands ++= Seq(compileWithMacroParadise),
addCommandAlias("compile", "compileWithMacroParadise")

sbt compile现在应该在运行 stateWithMacroParadise 之前对构建状态( compile )进行适当的修改任务。