Polymorphic ranges?

[Ali Çehreli]

On 05/01/2011 08:04 AM, Dmitry Olshansky wrote:
> On 01.05.2011 18:30, Andrej Mitrovic wrote:
>> I'm not sure how to use those wrappers though. Maybe I'm just doing it
>> wrong:
>>
>> http://codepad.org/eHIdhasc
>>
>> But it seems these wrappers have some problems, the docs say about the
>> interfaces:
>>
>> Limitations:
>> These interfaces are not capable of forwarding ref access to elements.
>> Infiniteness of the wrapped range is not propagated.
>> Length is not propagated in the case of non-random access ranges.
> Well, this compiles, you just need to pick suitable type of range
> 'interface', that's the subtle thingie:
> http://codepad.org/uE0nIwbk

To make it more convenient to other, I paste Dmitry Olshansky's code:

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

enum BufferSize = 10;

struct Work
{
     private float[BufferSize] _buffer;
     RandomAccessInfinite!(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 main(){}

I also paste the compilation output:

Line 6: enum declaration is invalid
Line 6: Declaration expected, not '='
Line 13: semicolon expected following function declaration
Line 13: Declaration expected, not '('
Line 17: no identifier for declarator buffer
Line 24: unrecognized declaration

>
> Limitations are caused by bug, that is going to get fixed eventually ;)
>

Ali