Range returning an array

[Steven Schveighoffer]

On Tue, 09 Apr 2013 18:09:07 -0400, Joseph Rushton Wakeling  
<joseph.wakeling at webdrake.net> wrote:

> On 04/09/2013 11:02 PM, Steven Schveighoffer wrote:

>> 3. For your specific situation, add lastFront():
>
> It's an interesting thought.  I don't think it's ultimately the right  
> way to go
> -- yes, my application rests strongly on finding the last value, but the  
> problem
> is very simply that popFront kills the value _before_ finding out if the  
> range
> is now empty.

Well here is another solution:

struct MySimulation(T)
{
	T[] var;
         T[] tmpvar;
	T diff, convergence;

	auto front() @property
	{
		return var;
	}

	bool empty() @property
	{
		return (diff < convergence);
	}

	void popFront()
	{
		tmpvar[] = var[];
		// update values in var
		// and calculate diff
		if(empty)
		{
			var[] = tmpvar[]; // revert
			var = null; // optional, detach from original array
		}
	}
}

You could also use alloca to avoid storing tmpvar as a struct member and  
also avoid allocation.

-Steve