What 28 frames are elided when dividing by zero in the REPL?

user_446554 0
Viewed 217
scala> 5 / 0
java.lang.ArithmeticException: / by zero
  ... 28 elided

Twenty eight frames elided for a simple arithmetic expression?! What are these frames, why does Scala need that many to do safe division, and why are they being elided in the first place?

divide-by-zero read-eval-print-loop scala
1 Answers
scala> import scala.util.Try
import scala.util.Try

scala> Try(5/0)
res2: scala.util.Try[Int] = Failure(java.lang.ArithmeticException: / by zero)

scala> res2.recover { case e: ArithmeticException => e.printStackTrace }
java.lang.ArithmeticException: / by zero
    at $line8.$read$$iw$$iw$$anonfun$1.apply$mcI$sp(<console>:13)
    at $line8.$read$$iw$$iw$$anonfun$1.apply(<console>:13)
    at $line8.$read$$iw$$iw$$anonfun$1.apply(<console>:13)
    at scala.util.Try$.apply(Try.scala:192)
    at $line8.$read$$iw$$iw$.<init>(<console>:13)
    at $line8.$read$$iw$$iw$.<clinit>(<console>)
    at $line8.$eval$.$print$lzycompute(<console>:7)
    at $line8.$eval$.$print(<console>:6)
    at $line8.$eval.$print(<console>)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at scala.tools.nsc.interpreter.IMain$ReadEvalPrint.call(IMain.scala:786)
    at scala.tools.nsc.interpreter.IMain$Request.loadAndRun(IMain.scala:1047)
    at scala.tools.nsc.interpreter.IMain$WrappedRequest$$anonfun$loadAndRunReq$1.apply(IMain.scala:638)
    at scala.tools.nsc.interpreter.IMain$WrappedRequest$$anonfun$loadAndRunReq$1.apply(IMain.scala:637)
    at scala.reflect.internal.util.ScalaClassLoader$class.asContext(ScalaClassLoader.scala:31)
    at scala.reflect.internal.util.AbstractFileClassLoader.asContext(AbstractFileClassLoader.scala:19)
    at scala.tools.nsc.interpreter.IMain$WrappedRequest.loadAndRunReq(IMain.scala:637)
    at scala.tools.nsc.interpreter.IMain.interpret(IMain.scala:569)
    at scala.tools.nsc.interpreter.IMain.interpret(IMain.scala:565)
    at scala.tools.nsc.interpreter.ILoop.interpretStartingWith(ILoop.scala:807)
    at scala.tools.nsc.interpreter.ILoop.command(ILoop.scala:681)
    at scala.tools.nsc.interpreter.ILoop.processLine(ILoop.scala:395)
    at scala.tools.nsc.interpreter.ILoop.loop(ILoop.scala:415)
    at scala.tools.nsc.interpreter.ILoop$$anonfun$process$1.apply$mcZ$sp(ILoop.scala:923)
    at scala.tools.nsc.interpreter.ILoop$$anonfun$process$1.apply(ILoop.scala:909)
    at scala.tools.nsc.interpreter.ILoop$$anonfun$process$1.apply(ILoop.scala:909)
    at scala.reflect.internal.util.ScalaClassLoader$.savingContextLoader(ScalaClassLoader.scala:97)
    at scala.tools.nsc.interpreter.ILoop.process(ILoop.scala:909)
    at scala.tools.nsc.MainGenericRunner.runTarget$1(MainGenericRunner.scala:74)
    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)
res3: scala.util.Try[AnyVal] = Success(())

The elided lines are basically the REPL's overhead of reading a line, compiling it into a class, and constructing an instance of the class, which is where the code written in the REPL is evaluated.

user_56412440
Related