Re: balloonText and DoublePercentEngraver

[Werner LEMBERG]

>> Thanks.  I normally use extra `"` to mark stuff that is not a
>> keyword.  It seems I should revisit that practice...
> 
> If we get syntax highlighting in the docs, that might be relevant.
> Quoted strings are just strings, but unquoted names can be
> recognized as builtins.

Good point.

> (Plus, I don't know why people quote
> engravers whereas nobody writes \new "Staff" or \override
> "NoteHead"."color".)

I did the former but never the latter :-)

>> Undocumented... While adding a balloon is probably exotic, being
>> able to modify other properties of a `DoublePercentRepeat` grob is
>> important.  To do that, you have to know where it is timewise.
> 
> Well, it's not very logical, but not entirely illogical either.
> [...]

I agree, but having a hint in the NR would be helpful.

>> ```
>> \once\override DoublePercentRepeat.slope = #.3
>> \repeat percent 2 { e'2 e' e' e' }
>> ```
>>
>> Would it be possible to make `\repeat` accept such overrides,
>> passing them down to the various repeat grobs?

> The best solution I can imagine is bringing DoublePercentRepeat in
> line with what it semantically represents by turning it into a
> spanner going through the two bars.

This might eventually be a good solution.  For example, the only way I
found to adjust the width of a double percent repeat was to use
`\newSpacingSection` and adjusting the `spacing-increment` parameter.
Additionally, if you add a `TextSpanner` grob like `rit. - - -`, the
first bar becomes wider than the second bar, which looks quite ugly.

> [...]  However, this is tricky to implement today because there is
> no provision for spanners to reserve space inside of break align
> groups -- you have to create cumbersome stub items. Note how this is
> more or less similar to the implementation problems with your
> wish[*] of having line spanners reserve space for the texts at their
> bounds.
> 
> I personally have too much on my plate to work on that at the
> moment.  It may be wise to open a tracker issue.

OK.  While Dan's solution (from another e-mail) to adjust properties
of `DoublePercentRepeat` grobs is sufficient, the problem with
`TextSpanner` grobs deserves an issue, now entered as

  https://gitlab.com/lilypond/lilypond/-/issues/6231


    Werner