Joseph Rushton Wakeling:
I'll implement R250/521 for you, though.
Please stop, I am not worth that, and I don't even know how much good that generator is. So for you it's better to focus on more important matters of the new random module. Extra generators can be added later if needed.
It'd be interesting to see if this has any speed implications.
Passing several cpu words by value for each generated value seems not very efficient. But this generator is for special situations, so a certain performance loss could be acceptable. And if the compiler is able to inline the functions, the data transfer overhead is removed, and most of the performance loss is restored (but I don't know if non-templated Phobos functions get inlined).