Re: Issue 4169: Line and page breaking syntactic sugar (issue 156400043 by address@hidden)

[Keith OHara]

On Tue, 21 Oct 2014 09:33:56 -0700, <address@hidden> wrote:

> I've decided to keep the reverts for the On predefs, since \once does
> not do what [the name implies] with these overrides.

Yuck.  The problem seems to be that the override takes effect at the first beat 
in a bar, after the paper-column for the previous barline has been generated, 
and the \once makes the override expire before the next bar.

Unfortunately this also means that
 \override Score.NonMusicalPaperColumn.line-break-permission = #'allow
  R1
only has effect /after/ the R1.

We have a workaround for that timing problem in \overrideProperty, and then 
\once works fine with

autoLineBreaksOn = {
 \overrideProperty Score.NonMusicalPaperColumn.line-break-permission #'allow
 \override Score.NonMusicalPaperColumn.line-break-permission = #'allow }

autoLineBreaksOff = {
 %?? \overrideProperty Score.NonMusicalPaperColumn.line-break-permission ##f
 \override Score.NonMusicalPaperColumn.line-break-permission = ##f }

I put the %?? because I'm not sure whether it is more intuitive if
  \autoBreaksOff
  R1
should forbid a break before the R1, or mean "here is your last chance to break, 
Lily".

> https://codereview.appspot.com/156400043/