Re: {SPAM 04.7} Re: {SPAM 01.9} Re: Tie across voices

[David Sumbler]

On Fri, 2018-05-04 at 23:55 +0200, Simon Albrecht wrote:
> On 04.05.2018 19:23, David Sumbler wrote:
> > 
> > It seems that if, in a
> > <<{\musicA} {\musicB}>>
> > passage, \musicA does not specify a new Voice, then the music
> > before
> > the << >> passage and, importantly, also the music afterwards will
> > all
> > be treated as belonging to the same voice.  Is that correct?
> Have a look at this example:
> 
> %%%%%%%%%%%%%%%%
> \version "2.19.80"
> 
> <<
>    c
>    c
>  >>
> 
> \new Staff
> <<
>    c
>    c
>  >>
> 
> \new Staff
> <<
>    c
>    \\
>    c
>  >>
> 
> \new Staff
> \new Voice
> <<
>    c
>    c
>  >>
> %%%%%%%%%%%%%%%%
> 
> resulting in the attached output.
> <<>> just combines music expressions simultaneously. Depending on
> which 
> contexts are explicitly created, separate implicit contexts will be 
> created or not.
> 
> Best,
> Simon

I have always found the implicit creation of contexts etc. rather
confusing, which is why I have been inclined to define the higher
elements of the structure explicitly.  I used even to have completely
unnecessary \bookpart-s etc. but I try to avoid that sort of thing now.
 On the other hand, I suppose I have rather tended to take the implicit
creation of Voices for granted.  Especially in the light of your
example, I am starting to think that perhaps I should make it a policy
always to define Voices explicitly.

As it is, I found your example quite hard to understand, and I dare say
I am not alone in that.  However, having experimented with it quite a
bit, I now see (I think) that:

Example 1: here the << informs Lilypond that what follows is music, but
the Staff and Voice themselves are created by each of the simultaneous
'c's, which otherwise have nowhere to go.

Example 2: here a Staff has already been created, so the simultaneous
notes already have somewhere to go and therefore appear on to the same
Staff.  I think that they each individually create a voice, since they
have separate stems and because of the warning that Lilypond gives.
 Both voices seem to have voiceOne style, presumably since nothing else
has been specified; Lilypond is therefore protesting about the
resulting collision.

Example 3: The << \\ >> construct causes each of the simultaneous notes
to have its own voice, specifically voiceOne and voiceTwo.  If I add
another \\ section the contents go into voiceThree etc.  Is that
correct?

Example 4: Here a voice is explicitly defined, and therefore Lilypond
understands that the simultaneous notes both have to go into that one
voice, rather than creating new ones: hence the doubled notehead on a
single stem.  If I add a third note at the same pitch, no more
noteheads are produced, but surprisingly Lilypond does not give a
warning.

Have I understood all of this correctly?  Sorry if this all seems
elementary, especially since I have been using Lilypond on and off for
several years.

The automatic creation of contexts is obviously very useful, especially
when one is just a beginner at Lilypond.  But I almost wish that there
were an option to turn it off, which would be useful for forcing
oneself to understand how this all actually works!

David