bug#15859: 24.3.50; Calc - dimensionless units again

[Roland Winkler]

On Sun Nov 22 2020 Michael Heerdegen wrote:
> "Roland Winkler" <winkler@gnu.org> writes:
> 
> > Say, the old expression is "7 m / (c s)" and I want to convert this
> > into a physically equal expression.  So I run calc-convert-units,
> > which will ask
> >
> >   (The expression is unitless when simplified) Old Units:
> 
> Yes, I agree that the command doesn't behave in a useful way here.
> 
> u s works for me here and seems to do what you want.

Thanks for confirming that the current behavior is not useful.  Long
ago, before Calc was merged into the GNU Emacs trunk.  Calc was
handling dimensionless units just fine, which is why I consider the
new behavior a bad regression.  Personally, am so annoyed by this
behavior that I run into too often that I have gone back to a
version of calc-units.el from old times before Calc was merged into
the GNU Emacs trunk.  (For myself, none of the changes that were
done since then to calc-units.el are significant or useful.)
I really would like to revert the broken changes in calc-units.el
and bring the relevant pieces of code back to what they used to be.
But I have not yet found the time to come up with a patch for this.