Having a generic container that handles all types of values except one only for policy reasons is rarely a good idea. If floating point instabilities should be

Having a generic container that handles all types of values except one only for policy reasons is rarely a good idea. If floating point instabilities should be a concern (yes), then not at the Map level. That would be a naive crutch. Why would you ever want a number to be stored in a floating point format - that is a much better question. Most of our numeric values don’t even correspond to the domain of floating point. For business and programming goals, -0 is a complete technical nonsense. NaN too, it should just raise an exception (there are quiet and signalling nans, everyone defaults to quiet). And so should non-low-level integer overflow, really, unless there is a software fallback. Intermediate calculations limited to a low fixed number of digits is nonsense. Accounting for constant rounding/formatting errors is also a nuisance. Builtin, first class citizen, hardware enabled, base 10 fixed point could be the answer. But there’s almost always either bigint-only which is barely used even in a standard library, or a serious performance hit which nobody wants. There would still be issues, but much less in practice. Floating point is a niche type suitable for “multimedia”, NNs and maybe few other special contexts. They are the default only because everyone on the hardware..runtime spectrum traditionally believes that ordinary numbers are not their responsibility.