Define div or / for Period division? about dates.jl

[aviks]

The typical usecase for division, I'd imagine would be date(x) - date(y)/ year(1). You'd want to multiply the result by something (eg, interest rate), which begs the question of whether the result of the division should be a bare number rather than a period (0.5 or even 1//2 instead of year(1/2))

But in real life, division is not so simple, you need to consider day count conventions (Actual/Actual or 30/365 etc ..). So I wonder if making this an error, rather than giving a naive result is better. cf: https://github.com/aviks/Ito.jl/blob/master/src/time/day_count.jl

In any case, I think / should not promote to div. They ask different questions in the domain: what fraction of of a year is a month vs how many months in a year.

[StefanKarpinski]

I agree with @aviks.

[quinnj]

Sounds good. To be clear, date(x) - date(y)/ year(1), is not allowed because you'd be trying to divide Day/Year. After ditching automatic Period conversions, I haven't figured out a more clean API for specifying a conversion strategy, so that's another issue for another day.