Re: Any chance to call Tango as Extended Standard Library

[Andrei Alexandrescu]

Sergey Gromov wrote:

Mon, 19 Jan 2009 06:15:06 -0800, Andrei Alexandrescu wrote:

Michel Fortin wrote:

Other possible things involves a rudimentary profiler (checking for the elapsed time at each loop iteration), or a progress monitoring template (notifying another thread of the progress of a particular task).

    foreach (task; progessUpdater(timeProfiler(listOfTasks)))
    { ... }

You can't compose iteration based on opApply. How would progessUpdater and timeProfiler look like? This example pretty much transforms your argument into mine :o).

I think "can't" is a bit strong a statement.  Let's see:

With opApply:

class progressUpdater(Collection)
{
  this(Collection c)
  {
    collection_ = c;
  }

int opApply(int delegate(ref ElementType!(Collection)) dg)

  {
    composed_ = dg;
    return collection_.opApply(&fancifier);
  }

private: int fancifier(ref ElementType!(Collection) el)

  {
    globalOnProgress();
    return composed_(el);
  }

Collection collection_;

  int delegate(ref ElementType!(Collection)) composed_;
}

I see. Very ingenious! Reversed flow of control all the way. Thanks.

Andrei