src/Pure/General/timing.scala

relevant timing as in ML;
more PIDE modules;

/*  Title:      Pure/General/timing.scala
    Module:     PIDE
    Author:     Makarius

Basic support for time measurement.
*/

package isabelle


object Timing
{
  def timeit[A](message: String)(e: => A) =
  {
    val start = java.lang.System.currentTimeMillis()
    val result = Exn.capture(e)
    val stop = java.lang.System.currentTimeMillis()

    val timing = Time.ms(stop - start)
    if (timing.is_relevant)
      java.lang.System.err.println(
        (if (message == null || message.isEmpty) "" else message + ": ") +
          timing.message + " elapsed time")

    Exn.release(result)
  }
}

class Timing(val elapsed: Time, val cpu: Time, val gc: Time)
{
  def is_relevant: Boolean = elapsed.is_relevant || cpu.is_relevant || gc.is_relevant

  def message: String =
    elapsed.message + " elapsed time, " + cpu.message + " cpu time, " + gc.message + " GC time"

  override def toString = message
}