bug#1018: 23.0.60; Calculator Units Table "weirdness"

[Jay Belanger <jay.p.belanger@gmail.com>]

David Hansen <david.hansen@gmx.net> writes:
...
>> The values are stored that way, instead of as a float, when they are
>> exact.
>
> What exactly is "exact"?

"Exact" means exactly "exact". :)

> Just to be a bit pedantic: the "meter" (and therefore every measure of
> length/surface/volume) is *not* exact, it's an experimentally
> determined quantity (the length that light travels 1/299792458
> seconds).

Right, so when the Calc units table says that c = 299792458 m/s, that is
exact by definition.  Many units are defined in terms of other units,
and then the values given in the units table are exact.  It's only
conversions between two experimentally determined quantities (such as an
astronomical unit and a meter) that are necessarily inexact.

When the units table is displayed, having a conversion factor that is a
float indicates that it isn't exact; if conversion factors like that
between a tsp and ml are going to be displayed as a float, then there
needs to be another indicator that some values are not exact.

Jay