Andrei Alexandrescu:
I think the "needs to support BigInt" argument is not a blocker - we can release std.rational to only support built-in integers, and then adjust things later to expand support while keeping backward compatibility. I do think it's important that BigInt supports appropriate traits to be recognized as an integral-like type.
Bigints support is necessary for usable rationals, but I agree this can't block their introduction in Phobos if the API is good and adaptable to the successive support of bigints.
If you, Joseph, or both would want to put std.rational again through the review process I think it should get a fair shake. I do agree that a lot of persistence is needed.
Rationals are rather basic (important) things, so a little of persistence is well spent here :-)
Bye, bearophile
