Re: New figured bass capabilities and some request

[John Mandereau]

Le samedi 15 octobre 2005 à 16:51 +0200, Han-Wen Nienhuys a écrit :
> John Mandereau wrote:
> > Why not  <6c 5> <6 4>  for a 6th with a continuation line?
> 
> because "c" is a non-generic.  We don't have any other part of the 
> syntax that works like that.
> 
>   \set useBassFigureExtenders = ##t
> 
> and
> 
>   \noContinuation
> 
> may be a bit on the verbose side, but they follow teh normal pattern of 
> LilyPond input, and therefore, they're easier to learn and understand. 
> Identifiers should be used to make the commands more convenient.
> 
You convinced me, but now I have to learn how to redefine a command


> > btw, I have other feature requests for figured bass, which have
> > certainly already been discussed on the lists:
> > 
> > 1) It would be great to have syntax for the plus sign (instead of using
> > a \markup): something like
> > 
> > <6* 3>
> > 
> > which would show in the output like
> > 
> > +6
> 
> what does +6 mean?

It means the 6th is raised by a semitone; it is often (but not always)
used for the leading-tone (the 7th degree of the scale).

For example, let's take the dominant seventh chord (in C Major <g b d'
f'>).

Its 3rd inversion (i.e. its position with the 7th at the bass -- in C
Major <f g b d'>) is described with bass figure +4, because the interval
between the bass note and the leading-tone is a(n augmented) 4th.

Similarly, the second inversion of this chord (with the 5th at the bass)
is described with bass figure +6.


The "+" sign is so common in bass figures that it would be tiring for
the user to type a long command for that, which would not be better than
using a \markup. I guess you have good reasons not to modify the parser
(in case you need do so to implement this syntax), but it would be
convenient that a "plus" could be added to a bass figure by simply
appending a single character, * or ~ or whatever is possible.

> 
> > 2) In baroque figured bass, accidentals and plus signs are after
> > numbers, whereas in modern figured bass, they are before (like current
> > Lilypond implementation). Could it be set with commands like
> > 
> > \set BassFigureStyle = #'modern
> > \set BassFigureStyle = #'baroque
> 
> this is already supported through the figuredBassAlterationDirection
> property.
> 
Oops, I should have read the program reference first...

\set figuredBassAlterationDirection = #1

simply did what I want.
Is it worth documenting it in the manual? If so, I would be glad to
submit a patch on the list.


> > 3) Two missing symbols, a slashed "5" for the diminished fifth and a
> > slashed "7" for the diminshed 7th, could be added to the Feta font.
> > 
By the way, the bass figure

6
"slashed 5"

means the second inversion of the dominant seventh chord.

> > How much is it for sponsoring these features?
> 
> Do you want to sponsor noContinuation too?
> 
Yes, if this code

\set useBassFigureExtenders = ##t
<6> <6 5> <6\noContinuation 5>

can give the attached output. Now, I don't see a real case where this
situation happens, but you never know -- maybe the Martians would need
it?

I wonder why there is only one continuation line for two bass figures
continued with the same duration. You must read the score carefully to
see that the continuation line vertical position is between the two
numbers, which is not obvious when you quickly read the score for the
first time. IMHO it would be more legible if there was one line for each
figure.

-- 
John Mandereau <address@hidden>

figuredBass.png
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