Getting equivalent elements in a range/array

[Andrej Mitrovic]

Fantastic work, thanks! I'll look into more detail tomorrow, but it
looks good so far. Just added a function helper and made the struct
typed:

import std.array;
import std.range;

struct EquivalentElements(T)
{
   T range;
   T front_;

   this(T range)
   {
       this.range = range;
       this.front_ = popEqualFront(this.range);
   }

   bool empty()
   {
       return front_.empty;
   }

   T front()
   {
       return front_;
   }

   void popFront()
   {
       this.front_ = popEqualFront(this.range);
   }

   private T popEqualFront(ref T range)
   {
       T front;

       if (!range.empty) {
           do {
               front ~= range[0];
               range = range[1..$];

           } while (!range.empty &&
                    (front[$-1] == range[0]));
       }

       return front;
   }
}

EquivalentElements!(Range) equivalentElements(Range)(Range r)
{
    return typeof(return)(r);
}

// test
void main()
{
    foreach (elem; equivalentElements([1, 1, 2, 3, 4, 4]))
    {
        writeln(elem);
    }
}