Re: NR: Document \remove "Keep_alive_together_engraver" (issue 318580043 by address@hidden)

[David Kastrup]

Urs Liska <address@hidden> writes:

> Am 17.02.2017 um 08:34 schrieb address@hidden:

>> Ok, I'll bite.  What kind of piano music is written like
>>
>> \score {
>>   \new PianoStaff <<
>>     \new Staff = "up" <<
>>       \structure
>>       \v.1
>>       \v.2
>>     >>
>>     \dyn.1
>>     \new Staff = "mid" <<
>>       \structure
>>       \v.3
>>       \v.4
>>     >>
>>     \dyn.2
>>     \new Staff = "lo" <<
>>       \structure
>>       \v.5
>>     >>
>>   >>
>> }
>>
>> Because that is the example underlying your report.
>
> Piano Music, at least starting with Liszt, all the way through into the
> 20th century and until today.
> The Ravel piece here requires five individual voices that are basically
> distributed among three staves (frequent staff changes included), but
> are printed partially on a three-stave PianoStaff and partially using
> only the standard two staves.
>
> I feel it's natural to use PianoStaff here and to tell it to french
> the middle system if empty.

PianoStaff is explicitly for the case where you want staves to be
frenched together.  Its name does not mean "Piano inside" but rather
"Use frenching conventions common in piano music".

And you actually would still not want it to french out multiple staves
in an orchestral context: it should retain at least the two outer
voices.

So one solution might be to remove the middle stave from the
Keep_alive_together_engraver's scope, with a proper setting of, uh,
VerticalAxisGroup.remove-layer ?

I'm a bit fuzzy on our current state in that area.

> What I think I'll write to the docs now is that you have the choice
> between resorting to GrandStaff (for the piano) or to remove the
> engraver.

There really is no point to removing an engraver when the sole purpose
of PianoStaff is to add it.  Our documentation should focus more on
keeping people on top of LilyPond rather than teaching them how to
stumble along when they have no clue.  Because there are a whole lot of
ways to do that and if we wanted to document all of them...

I mean, we have the discussion lists for that.  Ask one question, get
10 answers.  But we don't have the room for 10 answers in the
documentation, so we should pick the best one.

-- 
David Kastrup