Re: repeating bar numbers and rehearsal marks in frenched score

[Mark Knoop]

At 19:49 on 28 Jul 2016, David Kastrup wrote:
>Mark Knoop <address@hidden> writes:
>> At 17:43 on 28 Jul 2016, David Kastrup wrote:
>>>At any rate, I think the principal problem is that the
>>>Keep_alive_together_engraver is desired to keep the marks context
>>>alive with _either_ of the two voices under it.  That would sound
>>>like we should have some way of grouping the marks context with the
>>>_StaffGroup_ rather than the individual contexts.
>>>
>>>So should the Keep_alive_together_engraver stop at a
>>>VerticalAlignment? If you want to keep together the contexts in a
>>>vertical alignment (like a StaffGroup), you could still add another
>>>Keep_alive_together_engraver in the context carrying the
>>>Vertical_alignment_engraver.
>>
>> And I have no idea how to implement this.
>>
>>>Basically, we would add the hara-kiri-interface to VerticalAlignment
>>>as well?  Something like that?
>>
>> How would this be done? Just by adding the interface and Y-extent
>> calls in define-grobs.scm?
>
>No, this would be a more intrusive change likely involving the C++
>layer.  I'm not asking you to do this but rather whether this avenue
>sounds like fitting your (and the general) problem space well enough
>that it would be worthwhile to pursue.

I find that difficult to answer since I don't fully understand what the
user end code for this method would be.

I'm also unclear as to why you feel that this is unsuitable to be done
by the Keep_alive_together_engraver without further nesting. After all,
the documentation for this engraver states:

    These spanners are then tied together so that one will be removed
    only if all are removed.

which fairly precisely describes the use case. To me this seems a fairly
logical extension of the introduction of the remove-layer property.

Might you consider a further reworking of my approach using some
well-chosen symbol names for remove-layer? Perhaps:

- #removable: layer ignored by Keep_alive_together_engraver
- #alive-while-any-other: layer only removed if all others are dead
- integer: existing usage
- '(): existing usage

Thanks, M

--
Mark Knoop