Re: [PATCH] support for flagged crotchets in mensural notation

[Lukas Pietsch]

Werner LEMBERG <wl <at> gnu.org> writes:

> 
> 
> >> Well, accepting a bool is not a bad idea.  For example,
> >>
> >>   \override NoteHead.hollow = ##f
> >>
> >> could undo
> >>
> >>   \override NoteHead.hollow = #2
> > 
> > #f is accepted for all properties anyway.  #t isn't by default, however.
> 
> Ah, ok.  On the other hand, having the possibility to say
> 
>   \override NoteHead.hollow = ##t
> 
> to always enforce hollow noteheads makes probably sense, too.

I'm still not quite sure what you would expect the semantics to be. If we
keep it as a numeric property, but call it "hollow" rather than something
involving "black", we'll first of all have to redefine it: not "duration
beyond which notes are black", but "duration up to which notes are white".
"hollow=1" would then be the default for modern notation. If you want
support for boolean values too, "hollow=#t" might naturally mean "hollow for
all values throughout". But what would "hollow=#f" be? No hollow notes at
all, i.e. fully black notation? Or just the default, i.e. the same as
"hollow=1"?

Another technical question: I found that apparently if I'm going to declare
these new grob properties in scm/define-grob-properties.scm, I'll also have
to declare them as part of some interface somewhere else, otherwise I get
"cannot find interface for property" errors. Where should a new notehead
grob property like this be declared? As part of note-head-interface (i.e. in
lily/note-head.cc), or as part of some new interface (e.g.
"mensural-note-interface"), to be declared in scm/define-grob-interfaces.scm?

Lukas