Re: Polymorphic ranges?

[Ali Çehreli]

On 05/01/2011 07:30 AM, Andrej Mitrovic wrote:

I'm not sure how to use those wrappers though. Maybe I'm just doing it wrong:

http://codepad.org/eHIdhasc

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

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

enum BufferSize = 10;

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

/*
Error: cannot implicitly convert expression
(inputRangeObject(cycle(this._buffer[min..max])))
of type std.range.InputRangeObject!(Cycle!(float[])).InputRangeObject
to std.range.InputRangeObject!(float[]).InputRangeObject
*/

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.

Ali