Consider a separate library that allows to match the components of a Range

[mulkieran]

The two components of a Range are the value and the units.

A separate library need not be able to handle translation initially.

The library should handle fractions and integers for values, with sign. The default value is 0. The library need not handle Decimal if justbytes chooses to omit it.

The units should default to bytes.

--value=32 --units=GiB
--value=1/2 --units=KiB