Re: Possible bug with new \partial

[Simon Albrecht]

Am 16.08.2015 um 22:32 schrieb Mats Bengtsson:
> On 08/16/2015 10:05 PM, Simon Albrecht wrote:
> > Hello Mats,
> >
> > IIUC \partial serves to insert an additional amount of time, however 
> > in this example we actually need to skip a beat – thus call \partial 
> > with a negative duration, which is impossible :-)
> > So you need to insert \set Timing.measureLength = #(ly:make-moment 
> > 3/4) before the second bar in your example.
> > Is this documented differently? Else I wouldn’t consider it a bug, 
> > rather an inherent limitation.
> Please note that \partial has been changed very recently in the 2.19 
> versions. The documentation for 2.19.25, 
> http://lilypond.org/doc/v2.19/Documentation/notation/displaying-rhythms#index-_005cpartial-1 
> says that the duration specifies the remaining length of the current 
> measure, which in my example is zero.
You’re right of course. I should’ve looked there.
> Note also that my example works fine if I remove the R2*3 line 
> directly below \time 3/4.
Not quite: no (default) bar line is drawn.
Apparently, the crucial sentence is the last one in the NR section: ‘The 
|\partial| command sets the |Timing.measurePosition| property, which is 
a rational number that indicates how much of the measure has passed.’
I had tried to set measurePosition directly, but when used immediately 
before the new \time, neither 0 nor 4/4 worked as values.
What does work as expected is inserting \partial 2. at the beginning of 
bar 2, so probably we should document that the ‘remaining length of the 
current measure’ given through \partial can’t be zero.

Yours, Simon

>     /Mats
> > Yours, Simon
> >
> > Am 16.08.2015 um 21:28 schrieb Mats Bengtsson:
> > > Hi,
> > >
> > > I tried version 2.19.25 to typeset a piece that changes from 4/4 
> > > with an upbeat to 3/4 without an upbeat, in the middle of the piece. 
> > > The new \partial handling worked for all parts, except a part that 
> > > started with a multimeasure rest. Here's a small example 
> > > illustrating the problem. Uncommenting the \bar line makes things 
> > > slightly better but still wrong.
> > > \version "2.19.25"
> > > \relative c'{
> > > \time 4/4
> > > \partial 4
> > > c |
> > > d e f g |
> > > f2.
> > > %\bar "||"
> > > \partial 4*0
> > > \time 3/4
> > > R2.*3 |
> > > f4 ( a f ) |
> > > f2.
> > > R2.*3 |
> > > }
> > >
> > >
> > >    /Mats
> > >
> > >
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