more lyrics notation wishes

[Erik Sandberg]

Hi,

Here's a new issue on lyrics notation. It happens in choral music that 
different voices have _almost_ the same lyrics, and it only differs during a 
few bars. It is a common behaviour to split the lyrics at these bars only. 
Example: SATB. Everyone sings "lalala", and suddenly A+T sing "baz" while S 
sings "bar" and B sings "foo", after that everyone sings the same "lalala" 
again. (often "bar" and "foo" are sung wiht a rythm different from "baz" in 
addition). This is often notated as:

               bar
SA staff==================
        lalala baz lalala
TB staff==================
               foo

instead of the more rigorous but space-consuming:

        lalala bar lalala 
SA staff==================
        lalala baz lalala
TB staff==================
        lalala foo lalala 

With lilypond it is only fairly easy/natural to typeset the rigorous version, 
which is kind of a weakness.
There's a slightly related problem which I will write about in a separate 
mail.

Here's my thoughts on a new notation:

AFAIU, {\addlyrics \music \text} now pairs one LyricsVoice \text with \music, 
and adds this music to one staff. Now my suggestion is to make it possible to 
let \addlyrics pair several LyricsVoices in parallel, to different pieces of 
music, and adding these pieces of music to different voices in different 
staves. And that these pairings can change with time.

To illustrate, here's one vague notation proposal:

Let each note be tied to zero or one LyricsVoice (the LyricsVoice that 
contains the text that is sung to this particular note). Let \UseLyrics 
<LyricVoice name> be a command to set this (and \NoLyrics set it to no 
LyricsVoice, i.e. make the music invisible to \addlyrics). One lyric can be 
sung to many different notes, but the other way around is not possible.
Example:
\addlyrics 
  <<
    \Context Voice = A \notes {
      \voiceOne
      \UseLyrics sop e4 e e e | e4 e2 e4 | e1
    }
    \Context Voice = B \notes {
      \voiceTwo
      \UseLyrics sop c4 c c c | %first bar: sop text is used for the 4 c:s
      \UseLyrics alt c2 c2 | % alt text "baz baz" is sung to the two c2:s
      \UseLyrics sop c1 % sop text "bar" is used for the last note.
    }
  >>
  <<
    \lyrics \Context LyricsVoice = sop { la la la la | foo foo foo | bar }
    \lyrics \Context LyricsVoice = alt { baz baz }
  >>

For reference, the following is a way to achive the same output with the 
current syntax:
<<
 \context Staff = X \notes {s1}
 \addlyrics
   \context Staff = X \context Voice = sop {\voiceOne e4 e e e | e4 e2 e4 | 
e1}
   \context LyricsVoice = A \lyrics { la la la la | foo foo foo | bar }
 \addlyrics
   \context Staff = X \context Voice = alt {\voiceTwo c4 c c c | c2 c | c1 }
   \context LyricsVoice = B \lyrics { _ _ _ _ | baz baz | _ }
>>

This is just a wild idea.. There probably exist better choices of notation, 
perhaps even something similar to { la la la la << { foo foo foo } \\ { baz 
baz } >> bar } could be possible for some standard cases.

What do you think?

Erik