[CM] CMN key signature, bar lines, and accidentals

Larry Troxler lt@westnet.com
Sat, 28 Dec 2002 00:03:41 -0500

Hi all and sorry for the top-posting. I'm still trying to figure out why
my CM to CMN renderings always have redundant accidental and natural
signs, even though I use (automatic-naturals t) and
(redundant-accidentals nil).

I'm trying to sort this out this weekend by looking through the CMN
source code.
It certainly seems as though the framework is there in CMN to keep track
of key-signature accidentals, current measure accidentals, and the like.

So it would help me though to hear from people who have used CM for
example, to generate a CMN score. I know in years past there was a
section in the CM doc about this.
Was the result correct with respect to avoiding redundant accidental
signs, or not?

In other words, did this work in the past, or was it never the intention
that the CM -> CMN rendition was this knowledgeable about eliminating
redundant accidentals, and it was the intention that someone would tweak
the CMN output by hand if they wanted real notation output?

I just want to know if I'm dealing with a recently introduced bug, or if
it never worked this way to begin with, and people always tweaked the
CMN output manually before publishing it in Computer Music Journal or
the like.

Thanks in advance!

Larry Troxler

Larry Troxler wrote:
> (CC'd to list)
> Bill Schottstaedt wrote:
> >
> > > Do accidentals/naturals on note names in CMN correspond to what is
> > > notated, and not the frequency of the note?
> >
> > "A4" says nothing about an accidental and is ambiguous. Look for
> > "automatic naturals" in cmn.html.
> Ok, so I assume that the effect of "automatic naturals" is to add a "n"
> onto the specification of notes that don't specify any accidental?
> Although that helped, unfortunately as it turns out, I still have either
> a basic problem or basic misunderstanding. Consider this:
>  (cmn (redundant-accidentals nil) staff treble g-major (meter 2 4)
>        cs4 cs4 fs4 fn4 ds4 dn4 dn4 ds4)
> Setting "redundant-accidentals" to nil helps in that the second cs4 is
> not notated with a sharp sign. However, there are other problems:
> The first fs4 (in measure 2) is notated with a redundant sharp sign even
> though the key signature is g-major.
> The second dn4 (in measure 4) is notated with a redundant natural sign
> even though the key signature is g-major.
> Could someone enlighten me on this?
> This is _not_ a complaint about CMN, just a question about how it works.
> And I know that this is not a great problem if one is writing a CMN
> score directly, but it is a problem if we're using CMN to make a quick
> draft notation of Common Music output (for example).
> Not a fatal problem either, but just makes the output difficult to read.
> Larry Troxler
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