Re: Misleading autobeaming in 3/4

[Vaughan McAlley]

Bertrand Bordage wrote:
>Ok, I'll keep LilyPond's default beaming since it's the usual notation.
>Thanks!
>Bertrand

No! Beam it how _you_ like. Otherwise it’s like using Times font just
because it’s the Microsoft Word default :-) Just say you’re following
Debussy...

I ran into a similar problem recently with my first real-world use of
Lilypond. The music is from Mozart’s La Clemenza di Tito, and I needed
to follow Mozart’s beaming:

\relative c' {
    \key f \major
    \time 3/8
    \clef "bass"
    c8^"Default beaming (correct)" (e16 c g e) | c'8 [(\grace { d16[
c16 b c]} e16 c g e )] |
    d'8\staccato c\staccato b\staccato c r r |

    \autoBeamOff
    \times 2/3  { d,16^"Manual beaming" [f a] }
    \repeat unfold 2 { \times 2/3  { d,16 [f a] } }
    \scaleDurations #'(2 . 3) {
        g [ bes c] g [ bes c ] f, [ a c ] |
        e, [ g c ] f, [ a c ] bes, [ d g ] |
        c, [ e g ] c [ g e ] c [ bes g ] |
        f [ a c ] f, [ a c ] f, [ a c ] |
        f, [ bes d ] f [ d bes ] a [ c f ] |
        c [ f a ] c, [ f a ] c, [ e g ] |
    }
    r32 f, [ a c ] f [ a c a ] f [ c a f ] |
    r c [ e g ] c [ e g bes ] g [ e c bes ] |
    r f [ a c ] f [ a c a ] f [ c a f ] |
    r g [ b d ] g [ b d b ] g [ f d b ] |
    r c, [ e g ] c [ e g e ] c [ g e c ] |
    \autoBeamOn

    \set Timing.beatStructure = #'(1 1 1)
    \times 2/3 { d'16^"\set Timing.beatStructure doesn’t work" f a }
    \times 2/3 { d,16 f a }
    \times 2/3 { d,16 f a }
}

I now suspect \set Timing.beatStructure = #'(1 1 1) didn’t work
because Lilypond considers the beat to be a dotted quarter. Beam
exceptions look quite Schemish and involving triplets would be beyond
me. For the time signature engraver there is no difference between a
"scherzo" 3/4 or 3/8 or one in three, but for musicians there is a
difference and maybe it should be easy to specify at the beginning,
something like:

\time 3/8
\setBeat 8 % ...or \setBeat 4.

Also nice would be something that parses manual beaming into beam exceptions:

\specialBeaming { r32 f, [ a c ] f [ a c a ] f [ c a f ] | }
r c [ e g ] c [ e g bes ] g [ e c bes ] |
\EndSpecialBeaming

Disclaimer: I’m making all of these comments free from any knowledge
of Lilyponds internals :-)

Vaughan