Polymorphic ranges?

[Ali Çehreli]

On 05/01/2011 09:09 AM, Andrej Mitrovic wrote:
> Yeah it seems a common interface is what I should have used. I've
> tried it in numerous ways but I got the interface type wrong
> apparently. Thanks Dmitry.
>
> Here's a quick example:
> http://codepad.org/RhNiUHU2

To make it more convenient to others, I paste Andrej Mitrovic's code:

module cyclicBuffer;

import std.stdio;
import std.range;
import core.thread;
import std.random;

enum BufferSize = 10;

struct Work
{
     private float[BufferSize] _buffer;
     InputRange!(float) buffer;

     this(T)(T unused)
     {
         _buffer[] = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];

         buffer = inputRangeObject(cycle(_buffer[]));
     }

     void setNewRange(size_t min, size_t max)
     {
         buffer = inputRangeObject(cycle(_buffer[min..max]));
     }

     void setStep(size_t newStep)
     {
         buffer = inputRangeObject(stride(buffer, newStep));
     }

}

void main()
{
     writeln();
     auto work = Work(1);

     size_t count;
     int min;
     int max;
     size_t step;
     while (!work.buffer.empty)
     {
         write(work.buffer.front);
         stdout.flush();
         work.buffer.popFront;

         if (++count == 20)
         {
             min = uniform(0, BufferSize / 2);
             max = uniform(BufferSize / 2, BufferSize);
             step = uniform(1, 5);
             work.setNewRange(min, max);
             work.setStep(step);
             writefln("\nmin: %s, max: %s, step: %s", min, max-1, step);
             count = 0;
         }

         Thread.sleep( dur!("msecs")(100) );
     }
}

>
> I hope those bugs get squashed so I can have more fun with these ranges. :)

Ali