Studying D Programming Language...

I have recently decided to re-hash (sic) my algorithms, and to study the D Programming Language at the same time. Below you can see a cool heapsort implementation.

As I used the ZeroBUGS debugger to step through the code, I have noticed that the DMD compiler does not generate debugging info for the template parameters (a and b in swap, a in siftdown, and so on). I hope this glitch (and other related bugs) will be fixed before the next D Programming Language conference.

import std.stdio;

void swap(T)(inout T a, inout T b)
{
 scope tmp = a;
 a = b;
 b = tmp;
}

void siftdown(T)(inout T a, int begin, uint end)
{
 uint root = begin;
 while (root * 2 + 1 <= end)
 {
  scope child = root * 2 + 1;
  if (child < end && a[child + 1] > a[child])
  {
   ++child;
  }
  if (a[root] < a[child])
  {
   swap(a[root], a[child]);
   root = child;
  }
  else
  {
   break; 
  }
 }
}

void heapify(T)(inout T a, uint length)
{
 int start = length / 2 + 1;
 
 while (start >= 0)
 {
  siftdown(a, start, length - 1);
  --start;
 }
}

void heapsort(T)(inout T a)
{
 uint count = a.length;
 heapify(a, count);

 --count;
 while (count > 0)
 {
  swap(a[0], a[count]);
  --count;
  siftdown(a, 0, count);
 }
}

void main()
{
 long[] a = [ 5, 4, 1, 2, 100, 10, 42, 5, 10 ];
 writefln(a);

 writefln("----- heapsort -----");
 heapsort(a);
 writefln(a);
}