Re: Issue 34 in lilypond: Grace synchronization

[lilypond]

Comment #17 on issue 34 by address@hidden: Grace synchronization
http://code.google.com/p/lilypond/issues/detail?id=34

Comment by Keith O'Hara on bug-lilypond:

> However, in my eyes we need to distinguish the events at each moment.
> Basically, we have three different types of events:

> 1) events that should be processed at the very beginning of each moment
> (before grace notes are handled)
> 2) grace notes (i.e. notes that appear before the real content of the
> moment), possibly also including some \set command, which should not mess
> up things
> 3) normal notes

> In other words, we need to find a way to process key/clef/barlines (in
> particular all SetEvents) etc. before all grace notes. One approach might
> be to assign a moment like 0G-inf to them, so they will be processed  
> before
> all grace notes.

I think that is a promising approach.  I looked through the code thinking  
about
this issue two days ago, and began to look for a way to default-initialize  
the
grace_part_ of a Moment to something that would sort before any defined  
value
of grace_part_.  I do not know enough Scheme to know if Rational  
grace_part_ =
-1 / 0 is guaranteed to work as -inf.

It looks like most events should have effectively -inf for the grace_part_  
of
their timing.

The new method would need to take over the job that  
create_grace_fixup_list()
tries to do.  I am still figuring out how the list is created.