Re: Extra staves

[Mats Bengtsson]

Ralph Little wrote:
> Hi,
> I am trying to wangle the creation of a temporary extra staff that will
> appear below an existing staff for the duration of the extra part only.
> (Lily 2.0.1)
>
>
> |----------|------------------|------------
> |----------|------------------|------------
> |----------|------------------|------------
> |----------|------------------|------------
> |----------|------------------|------------ etc
>            |                  |
>            |------------------|
>            |------------------|
>            |------------------|
>            |------------------|
>
> I have seen the example in the tips and tricks, and the closest that I can
> get to what I am after is below.
>
> However, I am left with a couple of problems which I can't get my head
> around
>
>         * How can I easily remove the dangling clef and time sig from the
> new stave? Is the only way to create a new Staff context which excludes the
> engravers that I don't want, or is there an easier, neater way?

A very crude method is to set the Clef and TimeSignature objects to
\turnOff in your second Stave:
\context Staff = Two {
  \property Staff.Clef=\turnOff
  \property Staff.TimeSignature=\turnOff
  c4 d e f
}
However, there's a warning about using \turnOff in ly/property-init.ly.

I'm sure it's possible to remove an engraver from a single instantiation
of a context using the \applycontext function, but I have no idea about
the details of how to do it.

>         * How can I get rid of the dangling bar line at the beginning of the
> first staff, which I believe is coming from the Span_bar_engraver? I want
> the bar lines to span, but not the one at the left which is not attached to
> by new staff?

Both the Score and the StaffGroup contexts have one Span_bar_engraver
each. The former one gives the thin line, the latter gives the bracket.
If you want to get rid of both, you have to remove the engraver from
both contexts. The problem is if you have a score with several staves
and want the span bar for the normal staves but not for an occasional
additional stave like the one in your example.

For critical editions of music, it is fairly common to have these extra
staves for an alternative interpretation of the sources, for example.
I think the support for these things could be improved significantly
in LilyPond, unless someone has a better answer to your questions.

   / Mats