SBT插件 - 用户通过build.sbt定义的Command配置

Question

我正在编写一个添加命令的SBT插件,并希望用户能够通过在其中设置变量来配置此命令build.sbt.实现这一目标的最简单方法是什么？

以下是插件外观的简化示例:

import sbt.Keys._
import sbt._

object MyPlugin extends Plugin {

  override lazy val settings = Seq(commands += Command.args("mycommand", "myarg")(myCommand))

  def myCommand = (state: State, args: Seq[String]) => {

    //Logic for command...

    state
  }
}

我希望有人能够将跟随添加到他们的build.sbt文件中:

newSetting := "light"

如何String从myCommand上面的命令中将其作为变量提供？

Answer 1

看一下这里的例子:http://www.scala-sbt.org/release/docs/Extending/Plugins.html#example-plugin

在此示例中,定义了任务和设置:

val newTask = TaskKey[Unit]("new-task")
val newSetting = SettingKey[String]("new-setting")

val newSettings = Seq(
  newSetting := "test",
  newTask <<= newSetting map { str => println(str) }
)

然后,您的插件的用户可以newSetting在他们的build.sbt中为该设置提供自己的值:

newSetting := "light"

编辑

这是另一个例子,更接近你的目标:

Build.scala:

import sbt._                                                
import Keys._                                               

object HelloBuild extends Build {                           

    val newSetting = SettingKey[String]("new-setting", "a new setting!")

    val myTask = TaskKey[State]("my-task")                  

    val mySettings = Seq(                                   
      newSetting := "default",                              
      myTask <<= (state, newSetting) map { (state, newSetting) =>  
        println("newSetting: " + newSetting)                
        state
      }
    )

    lazy val root =
      Project(id = "hello",
              base = file("."),
              settings = Project.defaultSettings ++ mySettings)            
}

使用此配置,您可以my-task在sbt提示符下运行,并且您将看到newSetting: default打印到控制台.

您可以在build.sbt中覆盖此设置:

newSetting := "modified"

现在,当您my-task在sbt提示符下运行时,您将看到newSetting: modified打印到控制台.

编辑2

以下是上述示例的独立版本:https://earldouglas.com/ext/stackoverflow.com/questions/17038663/