Re: Arrow on cross-staves arpeggio

[David Sumbler]

On Wed, 2017-01-18 at 15:07 -0600, David Nalesnik wrote:
> arpeggioArrowUp will apply to a bottom context.  Rewriting its
> definition (in ly/property-init.ly) will work here:
> 
> arpeggioArrowUp = {
>   \revert PianoStaff.Arpeggio.stencil
>   \revert PianoStaff.Arpeggio.X-extent
>   \override PianoStaff.Arpeggio.arpeggio-direction = #UP
> }
> 
> Hope this helps--
> David

It definitely helps!  Thank you.

For my better understanding, could you explain exactly what is
happening here?

I take it that \arpeggioArrowUp applies to a Voice context, and that
somehow setting PianoStaff.connectArpeggios to #t doesn't alter this
fact.

But I don't understand what the 2 \reverts are doing in the new
definition.  What are they reverting to?  Perhaps #f and 0
respectively?

In the light of your reply I have now altered my file, and after a bit
of experimentation I find that all I need is:
        \set PianoStaff.connectArpeggios = ##t
        \override PianoStaff.Arpeggio.arpeggio-direction = #UP
and then
        \revert PianoStaff.Arpeggio.arpeggio-direction
when I no longer require the arrow (which is after the first
arpeggiando in this case).

David S