Re: Weird intermediate context creation

[Dan Eble]

On Jan 6, 2020, at 10:57, David Kastrup <address@hidden> wrote:
>> the current result is strange
> 
> Can you explain why you feel that?

I find it strange that this music produces these diverse results:

music = << c' e' >>

\new Score { % Case A: two notes in one voice
  \new Voice \music
}

\new Score { % Case B: two voices in one staff
  \new Staff \music
}

\new Score { % Case C: two staves
  \new StaffGroup \music
}

\new Score { % Case D: two staves
  \music
}

With my experimental changes, cases B, C, and D are rendered as two voices in 
one staff.  They are not rendered like case A (I believe) because I haven't 
touched the code that makes LilyPond create a new bottom context per item in 
\music.

> Implicit context creation is not going away.  Things like Global and
> Score context are created implicitly all the time.

I don't propose eliminating it.  Actually, I'm experimenting with generalizing 
some special handling of Score.  When LilyPond creates the implied intermediate 
contexts required for a new context, the current behavior is to avoid creating 
a new Score context if one already exists.  The question I asked myself is 
"What if LilyPond did the same for other intermediate contexts?"  Then I tried 
it and discovered the impact on the bend-bound test and some others.

> If I write
> 
> << \new Staff { c' } \new Voice { d' } >>
> 
> should the d' insinuate itself into the same staff as the c' ?

You didn't specify a staff for the d', so I don't see grounds for 
dissatisfaction if LilyPond were to do that.  Having said that, my work in 
progress produces the same output as master for this case, so it might not be 
something we need to debate.  I don't understand why yet, and I ought to, so 
thanks for this case.

Regards,
— 
Dan