Re: Change event properties before sending to engraver

[Valentin Petzel]

Something like this, yes. Essentially it is necessary to handle the events at 
Staff level, but not to loose the information about which Voice context we are 
coming from, some way or another way. 

I think this should be possible with the whole dispatcher-broadcasting system, 
but I do not know enough about it and as far as I see there is zero 
documentation on how this is used. That is why I am asking here.

Cheers,
Valentin

Am Montag, 20. März 2023, 21:19:13 CET schrieb Saul Tobin:
> Is your idea to have a second engraver at the Voice level to prepare the
> events? You should be able to have an engraver listen to the event and
> modify it before it's listened by the Staff level engraver, as long as they
> are \consist'ed in the right order.
> 
> On Mon, Mar 20, 2023, 1:40 PM Valentin Petzel <valentin@petzel.at> wrote:
> > Hello,
> > 
> > this is a more technical question targeted to the more experienced members
> > of
> > the list.
> > 
> > One thing that is stupidly hard to do in Lilypond is getting Slurs, Ties
> > and
> > other spanners to work between different Voices. The general approach is
> > to use
> > hidden notes, which is not at all nice to do or nice to read, and will
> > require
> > many extra voices in more complicated cases.
> > 
> > So one approach I’ve been trying to attempt is to move the respectable
> > Engravers to a higher context (Staff or even higher) and then make use of
> > Spanner ids to get the default behaviour.
> > 
> > Basically each Voice context would be assigned a unique voice ID, and this
> > ID
> > is by default used as spanner id. Then
> > 
> > <<
> > 
> >   { c8( d e d) } \\ { c( b) c( b) }
> > 
> > would still work, as these are Slurs with different spanner ids, but we
> > can
> > simply write
> > 
> > <<
> > 
> >   { c16\=1( d s8 } \\ { s c b\=1) }
> > 
> > to get a Slur between these Voices.
> > 
> > Of course this would still require some additional handling, as this will
> > add
> > unwanted support elements from other voices.
> > 
> > But the point here is that while the events have to eventually be handled
> > on
> > the Staff level we kind of need to "prepare" them at the Voice level to
> > have
> > the correct spanner id.
> > 
> > Thus I wanted to inquire if Lilypond has any mechanic that can be used for
> > something like this?
> > 
> > Alternatively one could use something like context properties to have
> > engravers communicate and send events and grobs to other engravers, but
> > surey
> > that would be messy.
> > 
> > Cheers,
> > Valentin

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