Proof of concept for v2 - NO duplication, NO `static if` hell, NO difficulty with interoperability

[Paul Backus]

On Monday, 1 November 2021 at 15:39:46 UTC, Andrei Alexandrescu 
wrote:
> On 11/1/21 10:09 AM, Ogi wrote:
>> On Sunday, 31 October 2021 at 01:59:38 UTC, Andrei 
>> Alexandrescu wrote:
>>> https://github.com/dlang/phobos/pull/8309
>>>
>>> Destroy!
>> 
>> Good stuff.
>> 
>> Notably absent are `std.range.interfaces`. What are we going 
>> to do about them?
>
> I don't think they need particular attention - either publish 
> them as they are, change them, or give up on them altogether (I 
> believe allowing ref-type ranges was a mistake).

Easiest thing would be to wrap the class reference in a struct 
that calls `save` in its copy constructor, but does not expose a 
`save` method to its users:

import std.range.interfaces;

struct ForwardRangeObject(E)
{
     private ForwardRange!E payload;

     @property auto ref front() { return payload.front; }
     // etc.

     this(ref inout typeof(this) other) inout
     {
         payload = other.payload.save;
     }
}