Re: keyAlterationOrder

[Freeman Gilmore]

On Wed, Dec 23, 2020 at 4:59 PM Carl Sorensen <carl.d.sorensen@gmail.com> wrote:

Freeman,

On Wed, Dec 23, 2020 at 2:41 PM Freeman Gilmore <freeman.gilmore@gmail.com> wrote:

On Tue, Dec 22, 2020 at 1:02 PM Mark Stephen Mrotek <carsonmark@ca.rr.com> wrote:

Freeman,

 

http://lilypond.org/doc/v2.19/Documentation/internals/key_005fengraver

I read through the Key_Engraver, url above, and related KeySignature and KeyCancellation.

The only details there, which I think I know, is how the pairs are constructed in the keyAlterationOrder.   And they have it wrong.    I believe it should read:  … step is a number from 0 to 6 and alter from  -2 (flat) to 2 (sharp)?   (Not -2 (sharp) to 2 (flat).)

No details are given as to how the alist order is read or constructed.    I do see The 5^th in the pairs (step).   I know that the alist cannot be read with assoc, at least in its simple form.

Any suggestions were the details of the keyAlterationOrderis explained?

That's the best documentation we have.  The next place to look is in the source.

Line 177 of ly/engraver-init.ly is where keyAlterationOrder is defined: 

https://gitlab.com/lilypond/lilypond/-/blob/master/ly/engraver-init.ly

.

When i go here I get a blank page with a menu on the left and nothing opens

keyAlterationOrder = #`(
    (6 . ,FLAT) (2  . ,FLAT) (5 . ,FLAT ) (1  . ,FLAT) (4  . ,FLAT) (0  . ,FLAT) (3  . ,FLAT)
    (3 . ,SHARP) (0 . ,SHARP) (4 . ,SHARP) (1 . ,SHARP) (5 . ,SHARP) (2 . ,SHARP) (6 . ,SHARP)
    (6 . ,DOUBLE-FLAT) (2 . ,DOUBLE-FLAT) (5 . ,DOUBLE-FLAT ) (1 . ,DOUBLE-FLAT) (4 . ,DOUBLE-FLAT) (0 . ,DOUBLE-FLAT) (3 . ,DOUBLE-FLAT)
    (3  . ,DOUBLE-SHARP) (0 . ,DOUBLE-SHARP) (4 . ,DOUBLE-SHARP) (1 . ,DOUBLE-SHARP) (5 . ,DOUBLE-SHARP) (2 . ,DOUBLE-SHARP) (6 . ,DOUBLE-SHARP)
  )

There are 4 sets with the same 7 keys 2 different orders of the keys.

There are several out there.   Here is one with the same accidental vertical not horizontal:

 keyAlterationOrder = #`(
      % Flats:
      (6 . -6/53)  (6 . -12/53)  (6 . -18/53)  (6 . -24/53)  (6 . -36/53)  (6 . -30/53)  (6 . -42/53)  (6 . -48/53)  (6 . -54/53)  (6 . -60/53)  (6 . -66/53)  (6 . -72/53)
      (2 . -6/53)  (2 . -12/53)  (2 . -18/53)  (2 . -24/53)  (2 . -36/53)  (2 . -30/53)  (2 . -42/53)  (2 . -48/53)  (2 . -54/53)  (2 . -60/53)  (2 . -66/53)  (2 . -72/53)
      (5 . -6/53)  (5 . -12/53)  (5 . -18/53)  (5 . -24/53)  (5 . -36/53)  (5 . -30/53)  (5 . -42/53)  (5 . -48/53)  (5 . -54/53)  (5 . -60/53)  (5 . -66/53)  (5 . -72/53)
      (1 . -6/53)  (1 . -12/53)  (1 . -18/53)  (1 . -24/53)  (1 . -36/53)  (1 . -30/53)  (1 . -42/53)  (1 . -48/53)  (1 . -54/53)  (1 . -60/53)  (1 . -66/53)  (1 . -72/53)
      (4 . -6/53)  (4 . -12/53)  (4 . -18/53)  (4 . -24/53)  (4 . -36/53)  (4 . -30/53)  (4 . -42/53)  (4 . -48/53)  (4 . -54/53)  (4 . -60/53)  (4 . -66/53)  (4 . -72/53)
      (0 . -6/53)  (0 . -12/53)  (0 . -18/53)  (0 . -24/53)  (0 . -36/53)  (0 . -30/53)  (0 . -42/53)  (0 . -48/53)  (0 . -54/53)  (0 . -60/53)  (0 . -66/53)  (0 . -72/53)
      (3 . -6/53)  (3 . -12/53)  (3 . -18/53)  (3 . -24/53)  (3 . -36/53)  (3 . -30/53)  (3 . -42/53)  (3 . -48/53)  (3 . -54/53)  (3 . -60/53)  (3 . -66/53)  (3 . -72/53)
      % Sharps:
      (3 . 6/53)  (3 . 12/53)  (3 . 18/53)  (3 . 24/53)  (3 . 30/53)  (3 . 36/53)  (3 . 42/53)  (3 . 48/53)  (3 . 54/53)  (3 . 60/53)  (3 . 66/53)  (3 . 72/53)
      (0 . 6/53)  (0 . 12/53)  (0 . 18/53)  (0 . 24/53)  (0 . 30/53)  (0 . 36/53)  (0 . 42/53)  (0 . 48/53)  (0 . 54/53)  (0 . 60/53)  (0 . 66/53)  (0 . 72/53)
      (4 . 6/53)  (4 . 12/53)  (4 . 18/53)  (4 . 24/53)  (4 . 30/53)  (4 . 36/53)  (4 . 42/53)  (4 . 48/53)  (4 . 54/53)  (4 . 60/53)  (4 . 66/53)  (4 . 72/53)
      (1 . 6/53)  (1 . 12/53)  (1 . 18/53)  (1 . 24/53)  (1 . 30/53)  (1 . 36/53)  (1 . 42/53)  (1 . 48/53)  (1 . 54/53)  (1 . 60/53)  (1 . 66/53)  (1 . 72/53)
      (5 . 6/53)  (5 . 12/53)  (5 . 18/53)  (5 . 24/53)  (5 . 30/53)  (5 . 36/53)  (5 . 42/53)  (5 . 48/53)  (5 . 54/53)  (5 . 60/53)  (5 . 66/53)  (5 . 72/53)
      (2 . 6/53)  (2 . 12/53)  (2 . 18/53)  (2 . 24/53)  (2 . 30/53)  (2 . 36/53)  (2 . 42/53)  (2 . 48/53)  (2 . 54/53)  (2 . 60/53)  (2 . 66/53)  (2 . 72/53)
      (6 . 6/53)  (6 . 12/53)  (6 . 18/53)  (6 . 24/53)  (6 . 30/53)  (6 . 36/53)  (6 . 42/53)  (6 . 48/53)  (6 . 54/53)  (6 . 60/53)  (6 . 66/53)  (6 . 72/53)
    )

So where is the order?    7 key each with 24 pairs.

It appears that the accidentals show up in the list in the relative order they will appear in a key signature.  They are grouped by the kind of alteration (flats, sharps, double flats, double sharps).  So for sharps, the first to appear in a key signature is f#, followed by c#, followed by g#, then d#, and so on.  For flats, we start with bb, then eb, then ab, and so on.

I now the order of 5th and 4th as you explain here. 

I don't know what other documentation you want.

Something that explains the way the alist is formed?  .

Thank you, ƒg

I hope this helps.

Carl