Re: Multiple repeat nested with alternative

[Hans Aberg]

On 12 Mar 2009, at 09:49, Werner LEMBERG wrote:

> > >                      ________     ________            ________     
> > > ________
> > >                     [1.      ]   [2.                 [1.      ]  [2.
> > > | x x x x | x x x x | x x x x :||: x x x x | x x x x | x x x x :||  
> > > x x x
> > > | x |
> > >     A         B         C            D         E          
> > > F           G
> > >
> > > The correct order of performance/reading should be:
> > > A B C A B D E F D E G
> >
> > Honestly, I would just scrap the repeats alltogether and write it
> > all out.  As a person reading this, I would be very confused by what
> > was meant.
>
> I strongly disagree.  This is standard notation since centuries; many
> works by Mozart, Beethoven et al. use exactly this.

Hindemith, "Elementary training...", p. 70, uses it. So it seems to be  
standard. Note the subtlety that the last alternative is without a  
terminating vertical bar, indicating a continuation.

It might suffice to support a syntax like
  \repeat volta 2 {A B}
  \alternative {C}
  \repeat volta 2 {D E}
    \alternative {F}
  G H I J ...
That is, simply indicating one alternative less than in the "volta".  
LilyPond could then infer that there should be another alternative  
mark added in the following measure.

Strictly speaking, this additional last alternative mark is redundant  
from the semantic point of view: drop it and the music should be  
played the same. (Though it may have to be there for traditional  
reasons.)

  Hans