Scala REPL在开始使用Scala.tools.nsc.解释器时崩溃

我试图使用

scala.tools.nsc.interpreter

来启用交互式调试（如Python的pdb/ipdb）：

跑步时，我得到的是：

$ scala repl.scala
foo: Int = 123

scala> "hello"   
java.lang.NullPointerException
    at scala.concurrent.Await$$anonfun$ready$1.apply(package.scala:95)
    at scala.concurrent.Await$$anonfun$ready$1.apply(package.scala:95)
    at scala.concurrent.BlockContext$DefaultBlockContext$.blockOn(BlockContext.scala:53)
    at scala.concurrent.Await$.ready(package.scala:95)
    at scala.tools.nsc.interpreter.ILoop.processLine(ILoop.scala:402)
    at scala.tools.nsc.interpreter.ILoop.loop(ILoop.scala:430)
    at Main$$anon$1.<init>(repl.scala:14)
    at Main$.main(repl.scala:1)
    at Main.main(repl.scala)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at scala.reflect.internal.util.ScalaClassLoader$$anonfun$run$1.apply(ScalaClassLoader.scala:70)
    at scala.reflect.internal.util.ScalaClassLoader$class.asContext(ScalaClassLoader.scala:31)
    at scala.reflect.internal.util.ScalaClassLoader$URLClassLoader.asContext(ScalaClassLoader.scala:101)
    at scala.reflect.internal.util.ScalaClassLoader$class.run(ScalaClassLoader.scala:70)
    at scala.reflect.internal.util.ScalaClassLoader$URLClassLoader.run(ScalaClassLoader.scala:101)
    at scala.tools.nsc.CommonRunner$class.run(ObjectRunner.scala:22)
    at scala.tools.nsc.ObjectRunner$.run(ObjectRunner.scala:39)
    at scala.tools.nsc.CommonRunner$class.runAndCatch(ObjectRunner.scala:29)
    at scala.tools.nsc.ObjectRunner$.runAndCatch(ObjectRunner.scala:39)
    at scala.tools.nsc.ScriptRunner.scala$tools$nsc$ScriptRunner$$runCompiled(ScriptRunner.scala:175)
    at scala.tools.nsc.ScriptRunner$$anonfun$runScript$1.apply(ScriptRunner.scala:192)
    at scala.tools.nsc.ScriptRunner$$anonfun$runScript$1.apply(ScriptRunner.scala:192)
    at scala.tools.nsc.ScriptRunner$$anonfun$withCompiledScript$1$$anonfun$apply$mcZ$sp$1.apply(ScriptRunner.scala:161)
    at scala.tools.nsc.ScriptRunner$$anonfun$withCompiledScript$1.apply$mcZ$sp(ScriptRunner.scala:161)
    at scala.tools.nsc.ScriptRunner$$anonfun$withCompiledScript$1.apply(ScriptRunner.scala:129)
    at scala.tools.nsc.ScriptRunner$$anonfun$withCompiledScript$1.apply(ScriptRunner.scala:129)
    at scala.tools.nsc.util.package$.trackingThreads(package.scala:43)
    at scala.tools.nsc.util.package$.waitingForThreads(package.scala:27)
    at scala.tools.nsc.ScriptRunner.withCompiledScript(ScriptRunner.scala:128)
    at scala.tools.nsc.ScriptRunner.runScript(ScriptRunner.scala:192)
    at scala.tools.nsc.ScriptRunner.runScriptAndCatch(ScriptRunner.scala:205)
    at scala.tools.nsc.MainGenericRunner.runTarget$1(MainGenericRunner.scala:67)
    at scala.tools.nsc.MainGenericRunner.run$1(MainGenericRunner.scala:87)
    at scala.tools.nsc.MainGenericRunner.process(MainGenericRunner.scala:98)
    at scala.tools.nsc.MainGenericRunner$.main(MainGenericRunner.scala:103)
    at scala.tools.nsc.MainGenericRunner.main(MainGenericRunner.scala)


Abandoning crashed session.

scala> 

$ scala repl.scala 

scala> 123
null

Abandoning crashed session.

scala> 

我做错了什么？为了调试目的，在程序运行期间，是否有更简单的方法插入交互式REPL？断点、单步执行和检查局部变量有时无法做到这一点

---

我在Scala 2.11.5上。

我不知道为什么这条评论没有神奇的星号：

  // start an interpreter with the given settings
  def process(settings: Settings): Boolean

因此，您可以：

scala> repl process s
Welcome to Scala version 2.11.4 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_25).
Type in expressions to have them evaluated.
Type :help for more information.

scala> :quit
res0: Boolean = true

或者你可以：

package myrepl

import scala.tools.nsc.Settings
import scala.tools.nsc.interpreter.{ ILoop, SimpleReader }

object Test extends App {
  val foo = 42
  val repl = new ILoop {
    override def printWelcome() = {
      intp.bind("foo", foo)
      super.printWelcome()
      echo("Customized...")
    }
  }
  val s = new Settings
  s.usejavacp.value = true
  repl.in = SimpleReader()
  repl process s
  /*
  repl.createInterpreter()

  repl.intp.bind("foo", "Int", foo)

  repl.loop()
  repl.closeInterpreter()
  */
}

及

而且

我要降级到2.11.4，因为repl崩溃错误

Sbt是通过

编辑：

私有的

globalFuture

阻碍了初创企业的发展：

object Solid extends App {
  val foo = 42
  val repl = new ILoop {
    override def printWelcome() = {
      super.printWelcome()
      echo("Customized...")
    }
  }
  val s = new Settings
  s.Xnojline.value = true
  s.usejavacp.value = true
  repl.settings = s
  repl.createInterpreter()
  repl.in = SimpleReader()
  repl.intp.initializeSynchronous()
  repl.loopPostInit()
  repl.globalFuture = concurrent.Future.successful(true)

  repl.intp.bind("foo", "Int", foo)

  try repl.loop()
  finally repl.closeInterpreter()
}

---

-Yrepl sync

选项在2.11中不再受欢迎。

您可以尝试Scalive:@GáborBakos:非常感谢；似乎非常有用！谢谢如果我将

.loop（）

调用替换为

.process（repl.settings）

，它会像广告一样工作，但是，evaling

foo

会产生

错误：找不到：value foo

-是否可以将名称绑定到repl？@ErikAllik启动需要重做，还可以看到sbt如何进行控制台初始化。misc init也有-i。在2.11.4或2.11.5上运行您的代码时保持不变，这会给我：

scala.reflect.internal.Symbols$CyclicReference:object Predef非法循环引用，或者打印相同的错误，但不会崩溃…@ErikAllik在
printWelcome
中调用
processLine
，这是我等待编译器初始化完成的最佳技巧。请参见编辑。嗯。
$ scalac myrepl.scala && scala myrepl.Test
foo: Int = 42
Welcome to Scala version 2.11.5 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_20).
Type in expressions to have them evaluated.
Type :help for more information.
Customized...

scala> foo
res0: Int = 42

scala> :quit

  s.Xnojline.value  = true
  //repl.in = SimpleReader()

  val repl = new ILoop {
    override def printWelcome() = {
      //import scala.concurrent.duration._
      //Await.ready(globalFuture, 10.minutes) // sorry, it's private!
      super.printWelcome()
      echo("Customizing...")
      processLine("") // block for init to finish
      intp.bind("foo", foo)
    }
  }

object Solid extends App {
  val foo = 42
  val repl = new ILoop {
    override def printWelcome() = {
      super.printWelcome()
      echo("Customized...")
    }
  }
  val s = new Settings
  s.Xnojline.value = true
  s.usejavacp.value = true
  repl.settings = s
  repl.createInterpreter()
  repl.in = SimpleReader()
  repl.intp.initializeSynchronous()
  repl.loopPostInit()
  repl.globalFuture = concurrent.Future.successful(true)

  repl.intp.bind("foo", "Int", foo)

  try repl.loop()
  finally repl.closeInterpreter()
}