Question

我在多项目build.sbt中初始化常用设置，如下所示：

lazy val commonSettings = Seq( version := "0.1", ..)
..
lazy val libs = Seq( "org.some" % "somelib" % "1.2.3", ..)
..
lazy val myProject = Project(..).
  settings(commonSettings, version := "0.2", libraryDependencies ++= libs)

鉴于

的定义

sbt.Project.settings(ss: Setting[_]*)

我很困惑这实际上有效，因为我在这里混合了Setting[_]和Seq[Setting[_]] args。我错过了什么，扁平化发生在哪里？

Answer 1

从sbt 0.13.8开始，定义更改为：

def settings(ss: SettingsDefinition*): Project =
  copy(settings = (settings: Seq[Setting[_]]) ++ ss.flatMap(_.settings))

这是展平的地方，SettingsDefinition定义为：

sealed trait SettingsDefinition {
  def settings: Seq[Setting[_]]
}

sealed class Setting[T] private[Init] (
  val key: ScopedKey[T], val init: Initialize[T], val pos: SourcePosition
) extends SettingsDefinition {
  def settings = this :: Nil
  ...
}

final class SettingList(val settings: Seq[Setting[_]]) extends SettingsDefinition

object SettingsDefinition {
  ...
  implicit def wrapSettingsDefinition(ss: Seq[Setting[_]]): SettingsDefinition =
    new SettingList(ss)
}

注意：

每个设置均为SettingsDefinition
任何Seq[Setting[_]]都会被自动提升为SettingsDefinition。

将Seq [Setting [_]]作为Project.settings（）args之一传递

1 个答案: