I supposed that it was recognised as the "speed of light", as this is commonly used in Physics. For instance, the Newtonian constant of gravitation can be expressed in m3 kg-1 s-2, but it is commonly expressed in GeV-2 c4 as well.
However, with units >= 0.5-0:
units::as_units("c")
#> Error: In ‘c’, ‘c’ is not recognized by udunits.
It seems that parse_unit() was identifying "c" as the "centi" prefix, and incorrectly returning this prefix as a unit until v0.5-0. This needs to be addressed ASAP in constants, as several CODATA constants are expressed in terms of the speed of light.
With
units < 0.5-0, the following code works:I supposed that it was recognised as the "speed of light", as this is commonly used in Physics. For instance, the Newtonian constant of gravitation can be expressed in
m3 kg-1 s-2, but it is commonly expressed inGeV-2 c4as well.However, with
units >= 0.5-0:It seems that
parse_unit()was identifying "c" as the "centi" prefix, and incorrectly returning this prefix as a unit until v0.5-0. This needs to be addressed ASAP inconstants, as several CODATA constants are expressed in terms of the speed of light.