Ranges and random numbers -- again

[Andrei Alexandrescu]

On 6/18/13 2:11 PM, Jonathan M Davis wrote:
> On Tuesday, June 18, 2013 10:39:38 Andrei Alexandrescu wrote:
>> On 6/18/13 10:16 AM, H. S. Teoh wrote:
>>> I say again that RNGs being passed by value is a major BUG. The above
>>> situation is a prime example of this problem. We *need* to make RNGs
>>> passed by reference. For situations where you *want* to duplicate a
>>> pseudo random sequence, an explicit method should be provided to clone
>>> the RNG. Duplication of RNGs should never be implicit.
>>
>> Occasionally copying a RNG's state is useful, but I agree most of the
>> time you want to just take a reference to it.
>>
>> I think a good way toward a solution is
>> http://d.puremagic.com/issues/show_bug.cgi?id=10404.
>
> That may be a good way to go about it, but the default such as what rndGen
> returns really should be a reference type, and only ranges whose state can
> actually be copied such that continuing to iterate over them gives the same
> values should be forward ranges IMHO. Using Class!T might be able to make it
> so that we can avoid needing a std.random2, but we'll probably still need some
> minor code breakage in there somewhere.
>
> - Jonathan M Davis

How about defining rndGenRef and putting rndGen on the deprecation path?

Andrei