Docs: automatic accidentals (was: Odd output)

[Keith OHara]

On Fri, 10 Dec 2010 01:46:24 -0500 James Lowe <address@hidden> wrote:>
> <http://lilypond.org/doc/v2.13/Documentation/notation/multiple-voices#Known-issues-and-warnings-30>
>
> PS To anyone else who knows, if this known issue does apply in this case, 
> thenit might be a good idea to not use the word 'chord' as that can mean 
> differentthings to different types of musicians - if you see what I mean. We 
> couldtherefore edit the documentation?

Good point.  The issue regarding accidentals is not limited to chords.
Also, LilyPond *does* support such chords, most of the time. (The relevant
reg-test is ‘accidental-placement-samepitch.ly’)

Would you consider editing what is below into a doc patch, James?
(I intend to offset my karma deficit with a doc patch for the new Dynamics 
context.)
 ~ Keith

(1) NR 1.5.2 Collision Resolution, known issues :

- There is no support for chords where the same note occurs
- with different accidentals in the same chord.
- In this case, it is recommended to use enharmonic transcription,
- or to use special cluster notation (see Clusters).

+ Chords containing more than two pitches within a staff space, such as
+ <e f! fis>4 , create collisions that are not resolved automatically.
+ Consider using an enharmonic transcription of one or more pitches,
+ or moving some pitches to a temporary separate voice,
+ or using cluster notation (see Clusters)
+ or creating a custom graphic (see
+ 
http://lilypond.org/doc/v2.13/Documentation/snippets/simultaneous-notes#displaying-complex-chords
 ).
+ Note that accidentals in such chords must be specified explicitly (see
+ 
http://lilypond.org/doc/v2.13/Documentation/notation/displaying-pitches#Known-issues-and-warnings-40
 ).

(2) NR 1.1.3 Automatic Accidentals, known issues, is no longer accurate :

- Simultaneous notes are considered to be entered in sequential mode.
- This means that in a chord the accidentals are typeset as if the notes
- in the chord happen one at a time,
- in the order in which they appear in the input file.
- This is a problem when accidentals in a chord depend on each other,
- which does not happen for the default accidental style.

+ Simultaneous notes are not considered in the automatic determination
+ of accidentals; only previous notes and the key signature are considered.
+ This can result in incorrect notation in cases where the same note name
+ occurs simultaneously with different alterations.
= The problem can be solved by manually inserting ! or ?
= for the problematic notes.