Minimally promoting division

[stevengj]

@DNF

How about defining your own function divide that has the wanted behavior?

Note that you can also define an infix operator by appending a subscript, e.g. /ᵣ.

@John_Gibson

Would defining // to be / for floating-point types be reasonable? Wouldn’t it be good to have this in Base?

This doesn’t seem crazy to me. It would ideally have to be done in Base to avoid type piracy.

@John_Gibson

I’d like my Newton Divided differences algorithm for polynomial interpolation to return rational polynomial coefficients if the x,y datapoints are given as integers or rationals

You could alternatively define:

newtondivdiff(x::AbstractVector{<:Integer}, y::AbstractVector{<:Integer}) =
    newtondivdiff(Rational.(x), Rational.(y))

and then just use / (which is exact for rationals or mixtures of rationals and integers).