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
