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## Re: Multiple repeat nested with alternative

 From: Mats Bengtsson Subject: Re: Multiple repeat nested with alternative Date: Tue, 17 Mar 2009 14:35:34 +0100 User-agent: Thunderbird 2.0.0.5 (X11/20070716)

I think some clarifications might be needed:


- LilyPond typesets the final alternative without a terminating vertical bar, except when the end of the alternative coincides with any of the following types of bar lines: ":|", "|:", "|.", ":|:", ":|.|:", ":|.:", ".|". Can any of you who have proposed a new \finalalternative please provide a simple example showing when such a feature would be needed, just as Valentine requested.


- One way to obtain the desired layout using current Lilypond features, has already been proposed.
 An alternative solution is
\relative c'{
\repeat volta 2 { a a a a | b b b b | }
\alternative{{c c c c | }{\bar ":|:" d d d d | }}
\repeat volta 2 {
% Trick needed to fool LilyPond to not typeset the "|:" bar line:
\once \set Timing.defaultBarType = "" \bar "|"
e e e e | } \alternative {{f f f f }{g g g g }}
}

Unfortunately, this hack will not work nicely together with \unfoldRepeats or MIDI output, for obvious reasons.

/Mats

Hans Aberg wrote:


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

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--
=============================================
Mats Bengtsson
Signal Processing
School of Electrical Engineering
Royal Institute of Technology (KTH)
SE-100 44  STOCKHOLM
Sweden
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