Any chance to call Tango as Extended Standard Library

[Sergey Gromov]

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_;
}

With ranges:

struct progressUpdater(Collection)
{
  this(Collection c)
  {
    collection_ = c;
  }
  
  typeof(collection_.head) head()
  {
    return collection_.head;
  }
  
  void next()
  {
    globalOnProgress();
    collection_.next();
  }
  
  bool empty()
  {
    return collection_.empty;
  }
  
  private Collection collection_;
}

Cannot see anything impossible with both.