[zokier]

> See above, rounding off and collecting error after every arithmetic operation is not the expected norm and what developers are taught.

Question is, is that a problem with developers or floats? :)

Ecosystem and tooling might help here, iirc that is something Kahan himself has been complaining about a lot. For example hypothetically you could have something like FP contexts or specialized high-level types where you can easily express how many digits are you expecting and the runtime/compiler would manage rounding etc so that you'd get more often correct results. Tbh that's just top of my head, and I didn't think too much about it.

But I think the question remains, how much of the problems are actually intrinsic to FP, and if you did actually cross t's and dot i's then would there still be some intractable problems in using FP with money? So is the problem "just" that FP can easily be misused, or that its impossible to use correctly?

I want to emphasize that I do not recommend anyone go using FP for money now. I'm just curious because its something I don't fully understand and well, HN has smart people that can hopefully help me there.

[wruza]

Question is, is that a problem with developers or floats?

Of course with floats. Requirements come from decimal-expecting people and developers have to convert requirements into an algorithm. If there’s a fundamental semantic or at least syntactic obstacle, it’s not a problem with developers.

Iow, if a language/system only has floats as “numbers”, it sucks for most business-level calculations.