adding 'HarmonicEvent?

[Marc Hohl]

Hello all,

I try to write a function that changes its argument to harmonics,
so
\makeHarmonic c4

should have the same effect as
<c\harmonic>4

I read Notation Reference 6.3.4, but the 'HarmonicEvent is
deep inside the 'elements list, so I think the only way to get this done
is to read the full structure and rebuild it, including the 'HarmonicEvent.

I remembered to have seen something similar in ly/chord-repetition-init.ly
and tried to modify the code here, but after struggling with the code
for about an hour or so, it still doesn't work at all. Can somebody please
explain to me how I can rebuild the argument to \makeHarmonic so that in 
includes
the desired 'HarmonicEvent entry?

Thanks in advance

Marc