protocol for using InputRanges

[Steven Schveighoffer]

On Thu, 27 Mar 2014 16:53:35 -0400, Walter Bright  
<newshound2 at digitalmars.com> wrote:

> On 3/27/2014 9:12 AM, monarch_dodra wrote:
>> If you initialized the next element in both constructor
>
> As mentioned earlier, requiring this of a range constructor makes it  
> impossible to separate composition of a range with using it.

Not impossible. Use lazy initialization.

> As also mentioned earlier, this throws under the bus entire categories  
> of use cases for ranges, all to avoid a single call to 'empty'.

This is going to look weird:

r.empty;

// now we can use it...

It only makes sense if you are using empty in your processing of the range.

-Steve